After changing IP addresses I lost the connection between master and client

[konstantinos]

Dear friends,
In the last few days they changed the IP addresses of the computers. I recorded the new addresses in the Veyon configuration of the master but unfortunately it does not "see" the client computers. On each computer in the list it says that it is offline or closed. Only one is okay and I didn't do anything different to it. Do you happen to know what has happened and how can I fix it?