RHEV upgrade from 3.6 to 4.0 fails with message "Execution of setup failed"

Issue

• RHEV upgrade from version 3.6 to 4.0 is failing with the below errors:

[ INFO  ] Starting dwh service
[ ERROR ] Failed to execute stage 'Closing up': Failed to start service 'ovirt-imageio-proxy'
[ INFO  ] Stage: Clean up
          Log file is located at /var/log/ovirt-engine/setup/ovirt-engine-setup-20160825143048-lylz6y.log
[ INFO  ] Generating answer file '/var/lib/ovirt-engine/setup/answers/20160825143402-setup.conf'
[ INFO  ] Stage: Pre-termination
[ INFO  ] Stage: Termination
[ ERROR ] Execution of setup failed

• Upgrading RHEVM 4.0 to RHVM 4.1 failed with below messages:

[ ERROR ] Failed to execute stage 'Environment customization': [Errno 2] No such file or directory: '/etc/pki/ovirt-engine/certs/imageio-proxy.cer'
[ INFO  ] Stage: Clean up
          Log file is located at /var/log/ovirt-engine/setup/ovirt-engine-setup-20180901123009-crkjlq.log
[ INFO  ] Generating answer file '/var/lib/ovirt-engine/setup/answers/20180901123244-setup.conf'
[ INFO  ] Stage: Pre-termination
[ INFO  ] Stage: Termination
[ ERROR ] Execution of setup failed