@Joakim77 Thanks for the picture, it helps a lot. Yes, the box with "telenor" on it must be ISP Router. It is connected to Ethernet switch TL-SG105E. If this setup was done by the Internet provider,...

@krisw In regard to rearranging, you may be overthinking it. It should be easy. Get "RJ45 network coupler" which looks like this: Unplug Main Deco from both Ethernet cables, plug them to network...

@krisw ISP routers usually come with more than one Ethernet port. If yours has at least two, it means you can connect switch directly to the router and whatever connected to another port - connect it...

@krisw So, you changed router and updated Deco firmware. Two changes, always challenging to figure which is responsible (or both, in combination). As a troubleshooting tip, I suggest to power off...

@Joakim77 "One of the X90's are connected through a switch that is connected to my modem" Do you mean: ISP Modem<--Ethernet-->Switch<---Ethernet--->Main Deco If yes, you may be having ISP router, not...

@Achilleas If you want to add another Deco node to your Deco mesh, you should buy additional M5. Deco X20 will not make much difference for your Deco mesh comparing with M5, but because X20 is on...