If you’re getting following error while accessing mod_sec from WHM, here is the quick solution for this.
The Mod Security plugin could not connect to the database. Please verify that MySQL is running. Error: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)
Login to your WHM with root access. Go to Service Manager from left menu. See if MySQL Service is enabled and being monitored. Check the boxes if unchecked.
Now access Mod Security from WHM. It should be working fine now.
Feedback are appreciated 🙂