We get more and more reports about the (usually false) error message when you try to login a Vault Server from a client in different versions and editions of Vault:
Vault Professional 201X is not compatible with the following applications on MyVaultServer:
Vault Basic Server 18.0.110
Vault Workgroup Server 18.0.110
Vault Collaboration Server 18.0.110
Vault Professional Server 18.0.110
In this situation you made sure that the edition of the Vault Server (for example Vault Collaboration) does match the edition of the Vault Client (for example Vault Collaboration).
In this situation the communication from Vault Client to the Vault Server via Port 80 is partially blocked/disturbed from another application or a faulty DNS entry in the network.
Following causes/solutions are known to this issue:
-different types of Antivirus programs. To make sure Antivirus is not the problem it needs to be fully uninstalled on Server and Client
-Proxyserver running in the environment
-DNS: change the windows hosts file (on client machine) via notepad and add the ip address and host name. You can find more information on this blogpost.
-Windows Firewall blocks the communicatin between Server and Client
-Another application which is using Port 80 blocks the communication
-(Update 20th June): there is another kind of this error where the IIS worker process consume an unusual amount of memory (check the windows event viewer on the Server) and as consequence stopps responding. An IISRESET usually solves the problem
-Update after a comment: another solution could be to perform a reinstall on the Vault Server installation via Control Panel - Programs and Features - Vault Server 201X - Repair or Reinstall - Reinstall