Ansible Automation Platform 2.5 installation fails with “Tunnel connection failed: 403 Tunnel or SSL Forbidden”

Issue

• When installing Ansible Automation Platform (AAP) 2.5, the following error is encountered during the task "Ensure automation gateway is ready":

  • Containerized setup installation failure

    TASK [ansible.containerized_installer.automationgateway : Ensure automation gateway is ready] **********************************
    fatal: [gateway.example.com]: FAILED! => {"attempts": 5, "changed": false, "elapsed": 0, "msg": "Status code was -1 and not [200]: Request failed: <urlopen error Tunnel connection failed: 403 Tunnel or SSL Forbidden>", "redirected": false, "status": -1, "url": "https://gateway.example.com:8446/api/gateway/v1/ping/"}
    

  • RPM based setup installation failure

    TASK [ansible.gateway_configuration.settings : Update automation platform gateway Settings] ***
    ESC[0;31mfatal: [gateway.example.com]: FAILED! => {"changed": false, "msg": "There was an unknown error when trying to connect to ParseResult(scheme='https', netloc='gateway.example.com:8443', path='api/gateway/v1/', params='', query='', fragment=''): URLError <urlopen error Tunnel connection failed: 403 Forbidden>"}