Hello everyone,

I'm experiencing a problem with my home network setup and I'm hoping someone here might have encountered a similar issue or can offer some advice.

Here's my current setup: I have two Wi-Fi routers connected to each other. The primary router (a FritzBox) is connected to the internet via my ISP and is being used as my main home network. The secondary router (My TP Link Archer C80), which is connected to the primary router through LAN to WAN, is intended to create a separate Wi-Fi network for my smart home devices.

Initially, everything worked well, but recently the secondary Wi-Fi network started to crash regularly after rebooting. The network still appears in my list of available networks and I am able to join it, but it is unable to access the internet. Interestingly, sometimes after rebooting both routers multiple times, the secondary network starts working again, but the issue keeps reoccurring regulary. When the issue occurs, I'm not able to see the router's IP address on my MacBook (Just empty space where the router IP Adress in the network settings should be), and my MacBook gets assigned an IP address that is not in the configured DHCP range of the secondary router. 

What's quite strange is that, even when the issue occurs and my Mac is unable to access the internet through the secondary Wi-Fi network, I can still access the router's information using the TP-Link Tether app on my smartphone via the cloud connection. According to the app, the router appears to be connected to the internet and it has to be in order to be accessed via the cloud mode in the Tether app if I am not mistaken (?). This inconsistency has left me puzzled, as I'm unsure why my devices that rely on the cloud all experience connectivity issues while the app suggests everything is fine with the router's internet connection.

If anyone has experienced a similar situation or has any insights into this discrepancy, I would greatly appreciate your input.

I've already tried several troubleshooting steps, including checking connections, resetting the routers, updating firmware, configuring different IP subnets and DHCP ranges. However, none of these steps seem to resolve the issue permanently.

The only thing I can think of is that I somehow made a mistake while setting up the static IP. But I really don't know where.

Here is a graphic clarify the setup:

Has anyone encountered a similar issue with a two-router setup or have any suggestions on what else I could try to fix the problem? I'd appreciate any advice you can offer.

Thank you in advance!