You may receive the error message "Shell access is not enabled on your account" when attempting to connect to your cPanel account over SSH. You will be disconnected from the server upon receiving this message. This is easily fixed.
As outlined in the message, shell access is not enabled. You can allow shell access on individual cPanel accounts through root WHM under the "Manage Shell Access" area. Just find the cPanel user in question in the list, and select the radio button for "normal shell" or "jailshell". Jailshell is more secure by disallowing the execution of some commands that may be harmful to the server and should be the go-to option for allowing shell access.
Once you've enabled shell access, you should then be able to login to the server via SSH.