I was upgrading my WHMCS billing software and ran into this errror:

SQLSTATE[HY000]: General error: 1615 Prepared statement needs to be re-prepared (SQL: select distinct setting, value from tblconfiguration)

According to the Billing software support, I need to increase the value of table_definition_cache in the server MySQL configuration.

I use WHM/cPanel and really don't know where to start. My googling hasn't helped much either.