Roundcube uses SQLite databases and an email user received one of the following errors when logging into Roundcube.
Too many redirects
The page isn't redirecting properly
This issue occurs when the email user's Roundcube SQLite database has become corrupt.
The corrupt database needs to be removed. If a database backup exists, the backup can be used to replace the corrupt database and minimize the loss of calendar and response data.
Removing the SQLite database will remove the email user's calendar events and responses.