Hello Chris,
just to make sure did you:
- set on server the unicast endpoint to be its proper IP address, make sure there is not several network interface
- set on client the static endpoints as IP of the server
- set on server “Engine/Programs/UnrealMultiUserServer/Saved/Config/<platform> Engine.ini” the unicast endpoint of the server
- Again on server “Engine/Programs/UnrealMultiUserServer/Saved/Config/<platform> Engine.ini” set the staticendpoints using IP of your clients
The last line was necessary to make it work on my network.
You can have a look there Multi-User Editing - Connecting in corporate environment - Pipeline & Plugins - Epic Developer Community Forums
If you still have the issue we will need to try replicate on our own vpn