I just saw this, sometimes I have trouble getting email, ends up in spam.
Did this eventually fininsh? I have seen issues on one host like this, that worked on all the others. Not sure why, I assume network issues.
Check that the agent can talk to the CM first and then verify that the CM is actually able to pull down a el7 parcel (I've seen this where only the el6 parcel was present and one node was el7). Then try shutting the agent down and clearing out the .flood folder from the path you mentioned before starting the agent again.
Overall hard to say exactly what's going on without more information.