@Rasim-Yilmaz You can't disable NAT loopback. If it's implemented in the router's FW then it's enabled by default, but there's no kill switch. Not every router model has this feature implemented.

@Spoonkb This issue usually has been fixed with a FW update - check this thread with a similar behavior. Just keep an eye for an online FW update.

@HenryMaister Go through this thread for more details on your inquiry. It's about different router model, but the same goes for C80.

@Zentry Did you try a different ethernet cables to rule out a cable issue ? You can try different switch port to rule out a switch port issue. In general you should connect your router to port5...

@tdhuff0803 Most likely these logs are part of the issue - check this thread for details on these logs. Try the suggestions there and make sure that your AX1800 is with the latest FW release. If...

@Novice1 The whole procedure of doing so has been described here. Keep in mind that even with the same SSID name, the RE450 emits another SSID. This would not be a wireless mesh network, where the...