half of my lab stopped working!
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I have a lab of 17 Ubuntu laptops. Everything was working fine. Did system updates this morning. Now 7 of the 17 computers work, the rest, the session crashed. This is the errors I get, any help would be appreciated! 2021-08-10T13:24:24.470: [WARN] LinuxServiceCore: server for session "/org/freedesktop/login1/session/c2" still running - killing now 
 2021-08-10T13:24:27.491: [WARN] QProcess: Destroyed while process ("/usr/bin/veyon-server") is still running.
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I have a lab of 17 Ubuntu laptops. Everything was working fine. Did system updates this morning. Now 7 of the 17 computers work, the rest, the session crashed. This is the errors I get, any help would be appreciated! 2021-08-10T13:24:24.470: [WARN] LinuxServiceCore: server for session "/org/freedesktop/login1/session/c2" still running - killing now 
 2021-08-10T13:24:27.491: [WARN] QProcess: Destroyed while process ("/usr/bin/veyon-server") is still running.
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Another clue. 
 When I start up the Lab PC's, it seems that Veyon is running as I can see the veyon icon in the task bar. However, when the master tries to connect, veyon crashes. I will try to generate new keys later and see if it does anything.
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It looks like we have a regression in 4.5.7 affecting some Linux users  Can set the log level to "Debug" on the affected computers and see if you can get additional information from Can set the log level to "Debug" on the affected computers and see if you can get additional information fromjournalctl -u veyon,/tmp/VeyonService.logand/tmp/VeyonServer.log?
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FYI: updated packages (4.5.7-2) for Ubuntu are available in the PPA which revert one change in the 4.5.7 which is suspected to cause the problems. Please report back if everything is OK again after upgrading. @tobydox 
 journalctl -u veyon produces these errors:
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.952: [DEBUG] PluginManager::loadPlugins(): discovered plugin "AuthKeys" at "/usr/lib/x86_64-linux-gnu/veyon/authkeys.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.954: [DEBUG] PluginManager::loadPlugins(): discovered plugin "BuiltinX11VncServer" at "/usr/lib/x86_64-linux-gnu/veyon/builtin-x11vnc
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.955: [DEBUG] PluginManager::loadPlugins(): discovered plugin "BuiltinDirectory" at "/usr/lib/x86_64-linux-gnu/veyon/builtindirectory.
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.955: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Config" at "/usr/lib/x86_64-linux-gnu/veyon/config.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.955: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Demonstration" at "/usr/lib/x86_64-linux-gnu/veyon/demo.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.955: [DEBUG] PluginManager::loadPlugins(): discovered plugin "DesktopServices" at "/usr/lib/x86_64-linux-gnu/veyon/desktopservices.so
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.956: [DEBUG] PluginManager::loadPlugins(): discovered plugin "ExternalVncServer" at "/usr/lib/x86_64-linux-gnu/veyon/external-vnc-ser
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.956: [DEBUG] PluginManager::loadPlugins(): discovered plugin "FileTransfer" at "/usr/lib/x86_64-linux-gnu/veyon/filetransfer.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.956: [DEBUG] PluginManager::loadPlugins(): discovered plugin "HeadlessVncServer" at "/usr/lib/x86_64-linux-gnu/veyon/headless-vnc-ser
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.960: [DEBUG] PluginManager::loadPlugins(): discovered plugin "LDAP Basic" at "/usr/lib/x86_64-linux-gnu/veyon/ldap.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.960: [DEBUG] PluginManager::loadPlugins(): discovered plugin "PowerControl" at "/usr/lib/x86_64-linux-gnu/veyon/powercontrol.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.960: [DEBUG] PluginManager::loadPlugins(): discovered plugin "RemoteAccess" at "/usr/lib/x86_64-linux-gnu/veyon/remoteaccess.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "ScreenLock" at "/usr/lib/x86_64-linux-gnu/veyon/screenlock.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Screenshot" at "/usr/lib/x86_64-linux-gnu/veyon/screenshot.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "ServiceControl" at "/usr/lib/x86_64-linux-gnu/veyon/servicecontrol.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Shell" at "/usr/lib/x86_64-linux-gnu/veyon/shell.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "SystemUserGroups" at "/usr/lib/x86_64-linux-gnu/veyon/systemusergroups.
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "TextMessage" at "/usr/lib/x86_64-linux-gnu/veyon/textmessage.so"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.962: [DEBUG] PluginManager::loadPlugins(): discovered plugin "UserSessionControl" at "/usr/lib/x86_64-linux-gnu/veyon/usersessioncont
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.962: [DEBUG] VeyonCore::initSystemInfo(): "4.5.7" "11-gilpin-lab" "linux" "5.4.0-80-generic" "Ubuntu 18.04.5 LTS" "ubuntu" "18.04"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.965: [DEBUG] ServiceDataManager::ServiceDataManager():
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.965: [DEBUG] PlatformSessionManager::PlatformSessionManager():
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.966: [DEBUG] LinuxServiceCore::connectToLoginManager(): connected to login manager
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.972: [DEBUG] PlatformSessionManager::openSession(): Opening session 0 for platform session "/org/freedesktop/login1/session/_36"
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.972: [INFO] LinuxServiceCore::startServer(): Starting server for new session "/org/freedesktop/login1/session/_36" with ID 0 at seat
 Aug 13 07:31:34 11-gilpin-lab veyon-service[3028]: 2021-08-13T07:31:34.973: [ERR] LinuxServiceCore::startServer(): Can't start Veyon Server in Wayland sessions as this is not yet supported. Please switch
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FYI: updated packages (4.5.7-2) for Ubuntu are available in the PPA which revert one change in the 4.5.7 which is suspected to cause the problems. Please report back if everything is OK again after upgrading. @tobydox 
 /tmp/VeyonService.log[sudo] password for david: 
 2021-08-13T07:29:31.530: [ERR] LinuxServiceCore: Can't start Veyon Server in Wayland sessions as this is not yet supported. Please switch to X11-based sessions!
 2021-08-13T07:31:34.952: [DEBUG] PluginManager::loadPlugins(): discovered plugin "AuthKeys" at "/usr/lib/x86_64-linux-gnu/veyon/authkeys.so"
 2021-08-13T07:31:34.954: [DEBUG] PluginManager::loadPlugins(): discovered plugin "BuiltinX11VncServer" at "/usr/lib/x86_64-linux-gnu/veyon/builtin-x11vnc-server.so"
 2021-08-13T07:31:34.955: [DEBUG] PluginManager::loadPlugins(): discovered plugin "BuiltinDirectory" at "/usr/lib/x86_64-linux-gnu/veyon/builtindirectory.so"
 2021-08-13T07:31:34.955: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Config" at "/usr/lib/x86_64-linux-gnu/veyon/config.so"
 2021-08-13T07:31:34.955: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Demonstration" at "/usr/lib/x86_64-linux-gnu/veyon/demo.so"
 2021-08-13T07:31:34.955: [DEBUG] PluginManager::loadPlugins(): discovered plugin "DesktopServices" at "/usr/lib/x86_64-linux-gnu/veyon/desktopservices.so"
 2021-08-13T07:31:34.956: [DEBUG] PluginManager::loadPlugins(): discovered plugin "ExternalVncServer" at "/usr/lib/x86_64-linux-gnu/veyon/external-vnc-server.so"
 2021-08-13T07:31:34.956: [DEBUG] PluginManager::loadPlugins(): discovered plugin "FileTransfer" at "/usr/lib/x86_64-linux-gnu/veyon/filetransfer.so"
 2021-08-13T07:31:34.956: [DEBUG] PluginManager::loadPlugins(): discovered plugin "HeadlessVncServer" at "/usr/lib/x86_64-linux-gnu/veyon/headless-vnc-server.so"
 2021-08-13T07:31:34.960: [DEBUG] PluginManager::loadPlugins(): discovered plugin "LDAP Basic" at "/usr/lib/x86_64-linux-gnu/veyon/ldap.so"
 2021-08-13T07:31:34.960: [DEBUG] PluginManager::loadPlugins(): discovered plugin "PowerControl" at "/usr/lib/x86_64-linux-gnu/veyon/powercontrol.so"
 2021-08-13T07:31:34.960: [DEBUG] PluginManager::loadPlugins(): discovered plugin "RemoteAccess" at "/usr/lib/x86_64-linux-gnu/veyon/remoteaccess.so"
 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "ScreenLock" at "/usr/lib/x86_64-linux-gnu/veyon/screenlock.so"
 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Screenshot" at "/usr/lib/x86_64-linux-gnu/veyon/screenshot.so"
 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "ServiceControl" at "/usr/lib/x86_64-linux-gnu/veyon/servicecontrol.so"
 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Shell" at "/usr/lib/x86_64-linux-gnu/veyon/shell.so"
 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "SystemUserGroups" at "/usr/lib/x86_64-linux-gnu/veyon/systemusergroups.so"
 2021-08-13T07:31:34.961: [DEBUG] PluginManager::loadPlugins(): discovered plugin "TextMessage" at "/usr/lib/x86_64-linux-gnu/veyon/textmessage.so"
 2021-08-13T07:31:34.962: [DEBUG] PluginManager::loadPlugins(): discovered plugin "UserSessionControl" at "/usr/lib/x86_64-linux-gnu/veyon/usersessioncontrol.so"
 2021-08-13T07:31:34.962: [DEBUG] VeyonCore::initSystemInfo(): "4.5.7" "11-gilpin-lab" "linux" "5.4.0-80-generic" "Ubuntu 18.04.5 LTS" "ubuntu" "18.04"
 2021-08-13T07:31:34.965: [DEBUG] ServiceDataManager::ServiceDataManager():
 2021-08-13T07:31:34.965: [DEBUG] PlatformSessionManager::PlatformSessionManager():
 2021-08-13T07:31:34.966: [DEBUG] LinuxServiceCore::connectToLoginManager(): connected to login manager
 2021-08-13T07:31:34.972: [DEBUG] PlatformSessionManager::openSession(): Opening session 0 for platform session "/org/freedesktop/login1/session/_36"
 2021-08-13T07:31:34.972: [INFO] LinuxServiceCore::startServer(): Starting server for new session "/org/freedesktop/login1/session/_36" with ID 0 at seat "/org/freedesktop/login1/seat/seat0"
 2021-08-13T07:31:34.973: [ERR] LinuxServiceCore::startServer(): Can't start Veyon Server in Wayland sessions as this is not yet supported. Please switch to X11-based sessions!
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FYI: updated packages (4.5.7-2) for Ubuntu are available in the PPA which revert one change in the 4.5.7 which is suspected to cause the problems. Please report back if everything is OK again after upgrading. cat /tmp/VeyonServer.log 2021-08-13T07:31:34.988: [DEBUG] PluginManager::loadPlugins(): discovered plugin "AuthKeys" at "/usr/lib/x86_64-linux-gnu/veyon/authkeys.so" 
 2021-08-13T07:31:34.990: [DEBUG] PluginManager::loadPlugins(): discovered plugin "BuiltinX11VncServer" at "/usr/lib/x86_64-linux-gnu/veyon/builtin-x11vnc-server.so"
 2021-08-13T07:31:34.990: [DEBUG] PluginManager::loadPlugins(): discovered plugin "BuiltinDirectory" at "/usr/lib/x86_64-linux-gnu/veyon/builtindirectory.so"
 2021-08-13T07:31:34.990: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Config" at "/usr/lib/x86_64-linux-gnu/veyon/config.so"
 2021-08-13T07:31:34.990: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Demonstration" at "/usr/lib/x86_64-linux-gnu/veyon/demo.so"
 2021-08-13T07:31:34.991: [DEBUG] PluginManager::loadPlugins(): discovered plugin "DesktopServices" at "/usr/lib/x86_64-linux-gnu/veyon/desktopservices.so"
 2021-08-13T07:31:34.991: [DEBUG] PluginManager::loadPlugins(): discovered plugin "ExternalVncServer" at "/usr/lib/x86_64-linux-gnu/veyon/external-vnc-server.so"
 2021-08-13T07:31:34.991: [DEBUG] PluginManager::loadPlugins(): discovered plugin "FileTransfer" at "/usr/lib/x86_64-linux-gnu/veyon/filetransfer.so"
 2021-08-13T07:31:34.991: [DEBUG] PluginManager::loadPlugins(): discovered plugin "HeadlessVncServer" at "/usr/lib/x86_64-linux-gnu/veyon/headless-vnc-server.so"
 2021-08-13T07:31:34.995: [DEBUG] PluginManager::loadPlugins(): discovered plugin "LDAP Basic" at "/usr/lib/x86_64-linux-gnu/veyon/ldap.so"
 2021-08-13T07:31:34.995: [DEBUG] PluginManager::loadPlugins(): discovered plugin "PowerControl" at "/usr/lib/x86_64-linux-gnu/veyon/powercontrol.so"
 2021-08-13T07:31:34.996: [DEBUG] PluginManager::loadPlugins(): discovered plugin "RemoteAccess" at "/usr/lib/x86_64-linux-gnu/veyon/remoteaccess.so"
 2021-08-13T07:31:34.996: [DEBUG] PluginManager::loadPlugins(): discovered plugin "ScreenLock" at "/usr/lib/x86_64-linux-gnu/veyon/screenlock.so"
 2021-08-13T07:31:34.996: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Screenshot" at "/usr/lib/x86_64-linux-gnu/veyon/screenshot.so"
 2021-08-13T07:31:34.996: [DEBUG] PluginManager::loadPlugins(): discovered plugin "ServiceControl" at "/usr/lib/x86_64-linux-gnu/veyon/servicecontrol.so"
 2021-08-13T07:31:34.997: [DEBUG] PluginManager::loadPlugins(): discovered plugin "Shell" at "/usr/lib/x86_64-linux-gnu/veyon/shell.so"
 2021-08-13T07:31:34.997: [DEBUG] PluginManager::loadPlugins(): discovered plugin "SystemUserGroups" at "/usr/lib/x86_64-linux-gnu/veyon/systemusergroups.so"
 2021-08-13T07:31:34.997: [DEBUG] PluginManager::loadPlugins(): discovered plugin "TextMessage" at "/usr/lib/x86_64-linux-gnu/veyon/textmessage.so"
 2021-08-13T07:31:34.997: [DEBUG] PluginManager::loadPlugins(): discovered plugin "UserSessionControl" at "/usr/lib/x86_64-linux-gnu/veyon/usersessioncontrol.so"
 2021-08-13T07:31:34.998: [DEBUG] VeyonCore::initSystemInfo(): "4.5.7" "11-gilpin-lab" "linux" "5.4.0-80-generic" "Ubuntu 18.04.5 LTS" "ubuntu" "18.04"
 2021-08-13T07:31:34.998: [DEBUG] FeatureWorkerManager::startUnmanagedSessionWorker(): Starting worker (unmanaged session process) for feature QUuid("{8e997d84-ebb9-430f-8f72-d45d9821963d}")
 2021-08-13T07:31:34.999: [DEBUG] VncProxyServer::start(): started on port 11100
 2021-08-13T07:31:34.999: [DEBUG] VncServer::prepare():
 2021-08-13T07:31:34.999: [DEBUG] VncServer::run(): running
 2021-08-13T07:31:35.003: [DEBUG] VeyonCore::exec(): Running
 2021-08-13T07:31:35.100: [DEBUG] FeatureWorkerManager::acceptConnection(): accepting connection
 2021-08-13T07:31:35.229: [DEBUG] ServerAuthenticationManager::processAuthenticationMessage(): state VncServerClient::AuthState(Init) type RfbVeyonAuth::Type(KeyFile) host "::ffff:172.16.0.42" user "LAPTOP-A7LR00H9\gilpi"
 2021-08-13T07:31:35.237: [DEBUG] ServerAuthenticationManager::processAuthenticationMessage(): state VncServerClient::AuthState(Challenge) type RfbVeyonAuth::Type(KeyFile) host "::ffff:172.16.0.42" user "LAPTOP-A7LR00H9\gilpi"
 2021-08-13T07:31:35.238: [DEBUG] ServerAuthenticationManager::performKeyAuthentication(): loaded public key from "/etc/veyon/keys/public/asus2/key"
 2021-08-13T07:31:35.238: [DEBUG] ServerAuthenticationManager::performKeyAuthentication(): SUCCESS
 2021-08-13T07:31:35.238: [DEBUG] AccessControlProvider::checkAccess(): no access control method configured, allowing access.
 2021-08-13T07:31:35.239: [INFO] ComputerControlServer::showAccessControlMessage(): Access control successful for "::ffff:172.16.0.42" "LAPTOP-A7LR00H9\gilpi"
 2021-08-13T07:31:35.406: [DEBUG] VncClientProtocol::receiveSecurityResult(): authentication successful
 2021-08-13T07:31:35.495: [DEBUG] ServerAuthenticationManager::processAuthenticationMessage(): state VncServerClient::AuthState(Init) type RfbVeyonAuth::Type(KeyFile) host "::ffff:172.16.0.42" user "LAPTOP-A7LR00H9\gilpi"
 2021-08-13T07:31:35.505: [DEBUG] ServerAuthenticationManager::processAuthenticationMessage(): state VncServerClient::AuthState(Challenge) type RfbVeyonAuth::Type(KeyFile) host "::ffff:172.16.0.42" user "LAPTOP-A7LR00H9\gilpi"
 2021-08-13T07:31:35.506: [DEBUG] ServerAuthenticationManager::performKeyAuthentication(): loaded public key from "/etc/veyon/keys/public/asus2/key"
 2021-08-13T07:31:35.506: [DEBUG] ServerAuthenticationManager::performKeyAuthentication(): SUCCESS
 2021-08-13T07:31:35.507: [DEBUG] AccessControlProvider::checkAccess(): no access control method configured, allowing access.
 2021-08-13T07:31:35.507: [INFO] ComputerControlServer::showAccessControlMessage(): Access control successful for "::ffff:172.16.0.42" "LAPTOP-A7LR00H9\gilpi"
 2021-08-13T07:31:35.813: [DEBUG] VncClientProtocol::receiveSecurityResult(): authentication successful
 2021-08-13T07:31:36.009: [DEBUG] FeatureManager::handleFeatureMessage(): feature "UserSessionInfo" command 0 arguments QMap()
 2021-08-13T07:31:36.010: [DEBUG] ComputerControlServer::sendFeatureMessageReply(): QUuid("{79a5e74d-50bd-4aab-8012-0e70dc08cc72}") 0 QMap(("0", QVariant(QString, ""))("1", QVariant(QString, ""))("2", QVariant(int, -1)))
 2021-08-13T07:31:36.010: [DEBUG] FeatureManager::handleFeatureMessage(): feature "FeatureControl" command 0 arguments QMap()
 2021-08-13T07:31:36.010: [DEBUG] ComputerControlServer::sendFeatureMessageReply(): QUuid("{a0a96fba-425d-414a-aaf4-352b76d7c4f3}") 0 QMap(("0", QVariant(QStringList, ("{8e997d84-ebb9-430f-8f72-d45d9821963d}"))))
 2021-08-13T07:31:37.156: [DEBUG] FeatureManager::handleFeatureMessage(): feature "FeatureControl" command 0 arguments QMap()
 2021-08-13T07:31:37.156: [DEBUG] ComputerControlServer::sendFeatureMessageReply(): QUuid("{a0a96fba-425d-414a-aaf4-352b76d7c4f3}") 0 QMap(("0", QVariant(QStringList, ("{8e997d84-ebb9-430f-8f72-d45d9821963d}"))))
 2021-08-13T07:31:37.156: [DEBUG] FeatureManager::handleFeatureMessage(): feature "UserSessionInfo" command 0 arguments QMap()
 2021-08-13T07:31:37.156: [DEBUG] ComputerControlServer::sendFeatureMessageReply(): QUuid("{79a5e74d-50bd-4aab-8012-0e70dc08cc72}") 0 QMap(("0", QVariant(QString, "david"))("1", QVariant(QString, "David Gilpin"))("2", QVariant(int, 0)))
- 
FYI: updated packages (4.5.7-2) for Ubuntu are available in the PPA which revert one change in the 4.5.7 which is suspected to cause the problems. Please report back if everything is OK again after upgrading. 
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@hammergil 
 After much time spent trying to get veyon to work on my Ubuntu 18.04 lab, and many days and weeks with not much support, I decided to end the suffering and move on. I did find an affordable paid option that I am using right now and it works great. Not only that but I did have a few issues after first install and the developer scheduled a zoom meeting with me on the same day of purchase and we got it all ironed out.So, if you are using Ubuntu and like me are stumped. If you are looking for an affordable solution, I can recommend Classroom Spy at classroomspy.com. Does the same thing as Veyon and I think I paid a 1-time cost of $699 for 25 computers.