the router is running in Router Mode because with Access Point Mode I can't use Mesh Network and we have 5 Repeater working as a mesh withe the Archer c6.

Does this have something to do with double NAT ? I know Access Point would avoid this but then I don't have mesh.

  @terziyski hi and thank you very much. I did the change today and had the following problem.

When I disconnected the WAN Port and connected the router with the LAN Port and gave it a LAN IP, everything worked perfect like the guide says.

My Laptop and other Computer with Wifi could connect to the Wifi and had the office ip.

BUT

all mobile Devices failed to connect to the internet. I mean the could connect to the Wifi and get an IP , DNS, Gateway etc (from the office nentwork)..., but they got the message that they are connected without internet, what caused the problem, that I couldn't browse the internet on mobile devices.

I think it's because the WAN Port is disconnected and the Archer C6 is giving the mobile devices the information that they are succesfully connected but the router has no internet, even if it gets the internet from the office router.

Laptops seems to ignore these message and can use the internet, but mobile devices like our Samsung A53 or our Samsung A7 Tablets can't browse the internet even if the have a valid IP Adress, DNS, Gateway, Subnet.

I don't know how to solve this problem.

  @terziyski 

Hello, here I must apologize, I had taken the screenshot when I reset everything back to working status,

so I could take a screenshot of what message I received when I connected the router correctly via LAN.

So I got these WAN Error message when logging in to webinterface after changing the router to LAN Connection withouth DHCP like the guide said.

I have corrected the screenshot.

Anyway, I checked everything after the change. Laptops and smartphones each had IP, subnet, gateway and DNS from the router 192.168.1.1 from the office network 192.168.1.0/24, only that the laptops and PCs came to the Internet and the smartphones did not.

They were connected to the wifi but just couldn't get on the internet despite having the correct IP.

I didn't understand this and put it down to the fact that maybe the smartphones can't get on the Internet because they are told there isn't one because the WAN port is no longer plugged in, while the laptops ignore this.

I have the exact same router at home, so I can always post it here.

Firmware is uptodate and I have rebooted all devices several times after the change.

The repeaters I have omitted for now to exclude sources of error.

  @h-maulwurf Good Morning.

I did the exact same set up now at my home and no device had an error, even the mobile devices are working perfectly. So it does work.

So the next thing I'll do is to repeat my steps in my company on a day when not every 20sec someone asks me why the wifi is not working :-)

Hi, I have EXACTLY the same problem.

Everything works just fine, but I noticed, as soon as I use the repeater I have problem and can't use the internet anymore.

With only the router, no problem at all, I can access the network and I am in the same subnet.

But when I connect the repeater and my laptop is using the repeater mesh, I have huge connections problems nad the internet is not available.

Why ?

  @terziyski I have exa tly the same issue at home with my ax55 and 2 ax 58 (it states on the box they're easymesh enabled but I don't think so, as they are version 1 not version 2). Also when it does work they're very unstable and drop out also although the easymesh sees the tether doesn't recognise them and I cannot get into their config). I connected via wps key and if I use ethernet cable I lose Internet.