Things to try... Reset to factory and re-enter your settings manually (not restore from backup). Swap the C5400s so the one that is not working is in place where the working one was. Ensure both are...

Back to my orginal advice. Switch the router out with a new one.

I never needed DMZ or port Triggering so do not know much about them. I use address reservation to reserve one of my IP address for a camera. Then use the Virtual Server to link that IP address to a...

I had a port forwarding issue with my Archer C8 when I installed new firmware that had the new green interface. After working with TP support, I went back to the older firmware (Blue interface) and...

They are all connected to some degree. For the average user, you do not need any of them and most cases all of them. However if you need to connect a security DVR, cameras, game machines, etc then...

I would try different names for each of the SSIDs.