PS4 App Can't Connect

I have a friend, who up until about a month ago, was able to access my Plex server via remote access on his PS4. He can still access via his Mac on the same network, however the PS4 app launches, stays on a black screen for 2 minutes and then gets a “can’t connect” error. He has even replaced the PS4 (without doing a backup/restore) and the issue persists. He’s able to sign in via the web browser on the PS4 however.

I have other friends who access the server on a PS4 without issue.

Any thoughts?