I sent the logs. It was not possible to understand the problem on my own because many messages and what the program does is hidden behind codes and general phrases.
At the moment, support has not helped.
I found out that if everything and the local password database are completely deleted, the first synchronization takes place (without a stamp or time in the Sync window). As a result, I see the following problems:
1. No last sync timestamp
2. The local database is not uploaded to the cloud
Installing on a clean VM gives the same result. I think the problem is on the server. We can only hope that technical support will do something about this and answer someday.