This issue is occurring because the SSL certificate being used by the machine is not valid according to SSL certificate validation rules. There are several reasons this could occur.
Incorrect hostname details set up in AttDBHostSettings.exe.
Time difference of around five minutes or greater between the workstation clock and the server clock.
The server is not on or accessible from the machine.
Below are some potential error messages and their fixes.
Certificate name mismatch:
Cause: The hostname in AttDBHostSettings.exe and the certificate are not the same.
Solution: Use the name found in CheckSSL.exe as the hostname. See: Manual entry of data connection string (Attaché workstation).
Invalid time:
Cause: Time difference between the workstation clock and the server clock.
Solution: Ensure the workstation and the server have the same time set in their clock.
Other Certificate issues:
Cause: Certificate may have become corrupted or out of date.
Solution: Reinstall Attaché workstation application which will update the certificate. See: Install the Attaché workstation.
Changed Server Name:
Cause: The server hostname was changed.
Solution: Reinstall Attache database server on the Attache Server. See: Install or upgrade Attaché Database Server.