Hi douglasroos and welcome to the Mattermost forums!
This sounds like a not working database migration.
Can you please disable the plugin in your system console, then enable debug logging and re-enable the plugin again? You should then (hopefully) see some additional loglines that might help us diagnose this issue further.
Also, if possible, please login to your PostgreSQL console, connect to your database and run the commands and post the outputs, please:
\dt focalboard*
select * from focalboard_schema_migrations;