How to use sync with VPN on Plex server?

I have noticed that if I try to sync a movie to my iPhone, it stops at 50% and won’t continue to download onto my iPhone. The only way to get it to finish is to disconnect my VPN and it finishes without any problems. So, hopefully a Plex employee can answer me. What can I do in order to get sync to work through a VPN?

I have the remote access working through my VPN, it shouldn’t be that difficult to get the sync to work through my VPN too. I just need to know how the feature works so I can figure out how to fix it. I’d really appreciate a Plex employee responding to this to explain what protocols and ports the sync uses in order to try to start fixing it.

I can’t believe I’m the ONLY person that has experienced problems with this set up. Plex, please respond to this!

I would appreciate a response as well.