Can't play on server using templated worlds

I'm trying to make worlds on a private Bedrock server. This works for worlds created without a template, but fails for templated ones (like Washington DC, Stonehill Castle, etc, which was for free in the Marketplace). The server shows the following error on startup:

 

DBStorage chain is invalid. Possibly encryption-related, or bad DBStorageConfig passed. Reason: Unable to decipher/decrypt LevelDB

[ERROR] Network port occupied, can't start server.

 

This doesn't have anything to do with the port as I can load worlds that I create myself with no problems. But this issue occurs whenever I make a server using a world from a template in the Marketplace, even if the world is for free.