If you're getting the following message:
'Fatal error has occurred.
Could not connect to database for SQL SessionHandler.'
Try running the following:
1. /scripts/upcp --force
2. /scripts/fullhordereset
3. /scripts/fixwebmail
4. /scripts/resethorde
If that does not fix the issue, you may have a corrupted database. To check and fix, login to your WHM and go to phpMYadmin and run the "Check and Repair" command.