Why the host failed to connect when the controller node is same as Execution node on Ansible Automation platform?

Issue

• Not able to connect to the controller node when executing the playbook from the same controller node.

• It shows the below error when trying to ping the controller node:

  fatal: [tower1.example.com]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: ssh: connect to host tower1.example.com port 22: Connection refused", "unreachable": true}