I found this on the fandom page because I was looking into server settings:

My progress got reverted, what can I do?
This is partially the previous desync problem, and another common mistake by shutting down the server incorrectly. The shutdown progression loss can be easily recognised as it happens after you kill your server. The way to prevent is to correctly shutdown your server by sending a SIGINT signal to it instead of terminating the process. On windows this can be achieved by sending a CTLR+C and accepting with a Y to the command window, on Linux you need to set up a trap and send the right signal or set up your service configuration to use SIGINT. As for restoring progress, you have no options, as it either never existed on the server or got lost by not saving the memory state.


This is for dedicated servers by the way.