If you updated your cabinet software or your Keywin 5 version, you might run into issues, when checking the synchronization log you find an error: (log is found in C:\ProgramData\Creone AB\KeyWin 5 Server)
relation "keys_" does not exist
Severity: ERROR
Code: 42P01
If so you have an issue where the cabinet software is not compatible with the Keywin 5 version you are running.
The solution is to either downgrade or upgrades the software version in keybox or Keywin 5 version, other circumstances might affect your decision. i.e. if you changed computer the computer might not be compatible with older keywin 5 versions, this you are forced to upgrade your keybox version.
The actual synch log looks like this, the error code is highlighted in red so you know what to look for:
Creone.CabinetSynchronizer.exe Error: 0 : 29.03.2018 13:09:03: Failed to execute synclog SyncLog {EntityAction=KeyCreatedOrUpdated, Id=4700, CabinetIdentifier=xxxxxe7d689ea15b123a12894xxxx, KeyIdentifier=0180be111a0000, UserIdentifier=, Argument=}: Npgsql.NpgsqlException:
relation "keys_" does not exist
Severity: ERROR
Code: 42P01