How to solve ERR_SSL_PROTOCOL error while accessing Control Panel
If the customer is facing the below error, then it can be resolved by adding the cusomer's IP in the Imunify360 Whitelist.
Step 1 Login into the directadmin control panel as admin
Step 2 Go to Imunify360 > Firwall
Step 3 Add the IP of the customer in the Add IP section as shown.

This should fix the issue.