I am trying to connect a mysql instance hosted on CPanel Cloud Platform.
I am using a connection string as follows(using the SQL Database ConnectorPlugin):
mysql://[dbuser]:[dbpassword]@[instance_public_ip_address]:[port]/[dbname]
Please remove the connection details you show here (as mentioned above), this is exposing data to anyone who wants to access your system.
Given the port you are connecting on, it might be a firewall issue as well since this is not typically available for outside connections (again as a security precaution) even though this is the connection port for MySQL.