Description of problem:
When you try to upload an invalid certificate, rhui-manager only provides the following error message:

The given certificate contains one or more entitlements that are
not compatible with the RHUI. For questions, please visit:
https://access.redhat.com/support/contact/customerService.html

User experience would be much better, and troubleshooting could start more efficiently, if the error message included the entitlement that wasn't compatible.

While trying to understand the recent issue brought up by Tapomoy, I (also) made the following change to /usr/lib/python2.7/site-packages/rhui/tools/cert_manager.py to force the responsible method to tell me which URL failed to validate against the predefined pattern, instead of just returning True/False:

def _is_valid_download_url(download_url):
<snip>
#    return fnmatch.fnmatch(download_url, VALID_URL_PATTERN)
    if fnmatch.fnmatch(download_url, VALID_URL_PATTERN):
        return True
    else:
        print download_url
        return False

The next attempt to upload the questionable pem file then produced:

# rhui-manager cert upload --cert /tmp/4361937509242360488.pem 
/content/eus/rhel/server/7/$releasever/$basearch/sap/os
The given certificate contains one or more entitlements that are
not compatible with the RHUI. For questions, please visit:
https://access.redhat.com/support/contact/customerService.html

Sure enough, it's not neat at all, but it helps. Please modify the code as appropriate to make rhui-manager explain -- print/log -- nicely which (first) entitlement is incompatible.

Version-Release number of selected component (if applicable):
rh-rhui-tools-3.0.3-3.el7ui.noarch