Master on Linux not finding Network Objects

[aknisly]

I'm impressed with this feature-rich software. Unfortunately, I'm struggling to get it working as it should. We have a terminal server running Cendio Thinlinc on Linux Mint 20.2. I've tried both v. 4.6.0 and 4.7.0.

There are no apparent problems with the Configurator, but no locations or computers show up in the Master, unless I open a terminal and do this:

su <another user>
sudo veyon-master

It seems to make no difference what user I'm logged in as, which user I su as, or which user I sign into Master as.

All of this is from local sessions. I've tested this from two other computers, running Linux Mint 19.2 and 20.2, using exactly the same configuration. Opening the Master normally, the computers to show up as expected in the Locations/Computers list. (Separate issues, but on the computer running 19.2, I haven't been able to get demo mode to work , and on the computer running 20.2, the Master isn't connecting/giving thumbnails of the other computers, nor is the Master running on the other two computers connecting to this computer.).

Here is my configuration file, with the network objects list truncated:

{
    "BuiltinDirectory": {
        "NetworkObjects": {
            "JsonStoreArray": [
                {
                    "Name": "Terminal Server",
                    "Type": 2,
                    "Uid": "{63778a78-13da-5edb-bd05-07bb091b1e48}"
                },
                {
                    "HostAddress": "192.168.10.200:11100",
                    "MacAddress": "78:ac:c0:3c:3e:9a",
                    "Name": "TS0",
                    "ParentUid": "{63778a78-13da-5edb-bd05-07bb091b1e48}",
                    "Type": 3,
                    "Uid": "{09522382-7ad3-5cc7-b965-a9bb44c1f344}"
                },
                {
                    "HostAddress": "192.168.10.200:11101",
                    "MacAddress": "78:ac:c0:3c:3e:9a",
                    "Name": "TS1",
                    "ParentUid": "{63778a78-13da-5edb-bd05-07bb091b1e48}",
                    "Type": 3,
                    "Uid": "{bdb7c052-3c7a-57a4-bcde-61077d426bbb}"
                },
                {
                    "HostAddress": "192.168.10.200:11102",
                    "MacAddress": "78:ac:c0:3c:3e:9a",
                    "Name": "TS2",
                    "ParentUid": "{63778a78-13da-5edb-bd05-07bb091b1e48}",
                    "Type": 3,
                    "Uid": "{b4fc591d-202f-54e5-b9f8-63600963d473}"
                },
                {
                    "HostAddress": "192.168.10.200:11103",
                    "MacAddress": "78:ac:c0:3c:3e:9a",
                    "Name": "TS3",
                    "ParentUid": "{63778a78-13da-5edb-bd05-07bb091b1e48}",
                    "Type": 3,
                    "Uid": "{b68f6f3b-cb6f-5eba-87cd-9ee220771a48}"
                },
                {
                    "HostAddress": "192.168.10.132:11101",
                    "MacAddress": "84:3a:4b:9b:11:0a",
                    "Name": "akn-w530_ts1",
                    "ParentUid": "{63778a78-13da-5edb-bd05-07bb091b1e48}",
                    "Type": 3,
                    "Uid": "{8b7827db-8486-43c3-8add-292af08ad0de}"
                }
            ]
        }
    },
    "Core": {
        "ApplicationVersion": "5",
        "InstallationID": "089ab44e-a665-4afb-9b6e-afdc89f02961",
        "PluginVersions": {
            "JsonStoreObject": {
                "{14bacaaa-ebe5-449c-b881-5b382f952571}": "1.1",
                "{1b08265b-348f-4978-acaa-45d4f6b90bd9}": "1.1",
                "{2917cdeb-ac13-4099-8715-20368254a367}": "1.1",
                "{2ad98ccb-e9a5-43ef-8c4c-876ac5efbcb1}": "1.1",
                "{387a0c43-1355-4ff6-9e1f-d098e9ce5127}": "1.1",
                "{39d7a07f-94db-4912-aa1a-c4df8aee3879}": "1.1",
                "{4122e8ca-b617-4e36-b851-8e050ed2d82e}": "1.2",
                "{4790bad8-4c56-40d5-8361-099a68f0c24b}": "1.1",
                "{63928a8a-4c51-4bfd-888e-9e13c6f3907a}": "1.1",
                "{67dfc1c1-8f37-4539-a298-16e74e34fd8b}": "1.1",
                "{6f0a491e-c1c6-4338-8244-f823b0bf8670}": "1.2",
                "{80580500-2e59-4297-9e35-e53959b028cd}": "1.2",
                "{8ae6668b-9c12-4b29-9bfc-ff89f6604164}": "1.1",
                "{a54ee018-42bf-4569-90c7-0d8470125ccf}": "2.0",
                "{d4bb9c42-9eef-4ecb-8dd5-dfd84b355481}": "1.0",
                "{ee322521-f4fb-482d-b082-82a79003afa7}": "1.1",
                "{f626f759-7691-45c0-bd4a-37171d98d219}": "1.0"
            }
        }
    },
    "LDAP": {
        "ComputerLocationAttribute": "",
        "ComputerLocationsByAttribute": "false",
        "ComputerLocationsByContainer": "false",
        "LocationNameAttribute": "",
        "UserLoginNameAttribute": ""
    },
    "Logging": {
        "LogLevel": "5"
    },
    "Master": {
        "AllowAddingHiddenLocations": "false",
        "AutoAdjustMonitoringIconSize": "false",
        "AutoOpenComputerSelectPanel": "false",
        "AutoSelectCurrentLocation": "false",
        "ConfirmUnsafeActions": "false",
        "HideComputerFilter": "false",
        "HideEmptyLocations": "false",
        "HideLocalComputer": "false",
        "ShowCurrentLocationOnly": "false"
    },
    "Network": {
        "VeyonServerPort": "11100"
    },
    "NetworkObjectDirectory": {
        "Plugin": "{14bacaaa-ebe5-449c-b881-5b382f952571}"
    },
    "Service": {
        "MultiSession": "true",
        "RemoteConnectionNotifications": "true"
    }
}

Thanks much in advance.