How to resolve spacewalk-repo-sync repository does not have a valid SSL certificate?

Issue

spacewalk-repo-sync fails with an error like:

root@sat58# /usr/bin/spacewalk-repo-sync -c customrepository -v

10:07:21 ======================================
10:07:21 | Channel: customrepository
10:07:21 ======================================
10:07:21 Sync of channel started.
10:07:22 Repo URL: http://mirrorrepos/repos/qa/customrepository/
10:07:22 ERROR: Repository ['http://mirrorrepos/repos/qa/customrepository/'] does not have a valid SSL certificate.
10:07:29 Sync of channel completed in 0:00:07.
10:07:29 Total time: 0:00:07