You may need to restart SSH on Cpanel server with default settings to get SSH access. This may needed when you work on a server with unknown SSH port or when SSH service on the server is failed/limited for some reason.
To fix SSH, login to WHM, then access following URL
/scripts2/doautofixer?autofix=safesshrestart
URL will look like
https://HOST:2087/cpsess1142682886/scripts2/doautofixer?autofix=safesshrestart