Help: Backup with out setting maintenance mode on

I am new to nextcloud. I tried to backup nextcloud using in rsync. I did not set maintenance mode to on. Now I can not get on nextcloud using web. I am running nextcloud on a raspberry pi setup.
–My desktop version of NextCloud says it is offline.
–I receive Internal Server Error when attempting to connect to nextcloud over web.
I am familiar with Linux.
I would appreciate any suggestions to resolve.

Thanks in advance.