Site crash after backing up

Hi, today after backing up my database, it failed to load with simply a blank page which said, and apologies for not writing it down but was feeling panicked, but something like “cannot access database.”

I went into the plugins folder and renamed the WP-DBManager folder to WP-DBManager.bak
I was and still can now load my site once again.
Have been using the plugin for years and have never had a problem with it until now.

Love this plugin so any info to correct the problem would be appreciated.

Pete