We are seeing the same issue on a number of machines, but only with the repository. They are all able to connect to ePO and download policies etc, but software installations or dat updates fail.
The majority of the time we see the same "Unable to find a valid repository" error, but occasionally it gets a little further, failing whilst attempting to download one of the xml files.
Okay, I am not quite sure what the issue was, but it is resolved now. After a day of the products not installing, I moved the system to another group that had no Deployment tasks. After the system got the new policies, I moved it back. Then after it got the policies again, the install went fine.
It's working again for us as well, no changes were made as far as our deployment tasks go, so I suspect McAfee had an issue with one of their repositories.
This was one the known issue identified with POD 1 in the ePO cloud 11:15 GMT on 06/13/2017 and our engineering team have fixed the issue the same day.