STUN issues with Unifi Controller

Out of the blue I started to have STUN issues with my Unifi Controller. I did wasted probably 2 hours before I figured it out. My controller is in one place and this specific site is in another location. Since I recently replaced routers and went from Sophos to OPNSense I was concerned that there was something wrong with the router. Turns out it was a coincidence.

My research on the internet was focusing on Port 3478 and that it needed to be open. When using tools like the ports was showing closed. I know it was port forwarded correctly and I know I had it open on the server. I just didn’t understand.

Fortunately, I remembered someone stating that their Controller Hostname/IP said something generic. This was in the controller itself. I thought it always said that but now I am beginning to think that some update changed that IP on me. I have had this setup for over a year and it just recently started to do this.

After making the change and putting in the correct IP the STUN notifications went away. I really hope this solves my random AP drops as well.