Change my DataBase from Single to Cluster

Hello together,

Today I moved my database server from a single node to a cluster and simply changed the config here at MAttermost. I did not take the database itself with me, but wanted to start from a “new” database.

But now I can (unfortunately) no longer log in to the WEB page. Under the CLI
I get the error message

Error: cannot read user credentials, maybe you need to use login first:

Who can help me here? What trick is there to get this working again?
Best regards

Z. Matthias

With CLI you mean the mmctl binary?
Can you please post all log lines out of your mattermost.log file (usually located in /opt/mattermost/logs/mattermost.log) when you restart the server?