@TPluddite In the this situation, I would set AX1800v in bridge mode and use only the Deco (in router mode) for wireless access. If you can't set the AX1800v in bridge mode then just disable its...

@ronname You can see the power adapter voltage on the adapter itself - if it's (100V-240V) the you can use it in Cyprus. Its FW been stated as Multilanguage, but unless you have a change language...

@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...