Ben and Doug, problem solved!
Turns out the Filmhub site had conflicting info. In one area it said to only send a film with the ProRes 422 HQ codec, but at another place they state they didn’t encourage 4444 XQ because of storage issues on their end. Since my film is only 75 minutes long the exported file turned out to be just 64GB and it was accepted.
Thanks again to both of you for your help!