WLAN: Why do interruptions occur for a few seconds every 6 minutes?

I finally got a decent DSL speed so that I can work in the home office. In the course of this, I completely renewed my home network: I'm using the current Fritz! Box 7590 on the ground floor next to the telephone socket and on the 1st floor a Fritz! Repeater 1200 connected via LAN in order to use it as an access point. All devices are completely automatically configured in the mesh with the current Fritz! -OS 07.21.

Unfortunately, during online meetings on a WLAN laptop (MacBook Pro 2016) on various platforms, the connection breaks for 5-10 seconds every 5-6 minutes.

To isolate the problem, I sent ping messages to 8.8.4.4 on my wireless laptop for an hour and logged them. The result: about 8 pings do not come back every few minutes. There are no problems with my computer connected by a patch cable (apart from the fact that a single ping can sometimes take 200ms irregularly?).

I let the mesh set itself completely: My laptop is currently connected to channel 100 (5Ghz Wi-Fi-ac, 80MHz width). It makes no difference whether the access point is active or not. The connection parameters and transfer rates via WLAN are excellent.

In the detailed WLAN log of the Fritz! Box says exactly at the times concerned that the MacBook was "logged off" and "logged on" a few seconds later.

Do you have a suggestion how I can solve the problem?

Difficult problem… Have you ever entered the Macbook's IP as unchangeable on the router?

You can also restrict the DHCP address range and maintain a small part of the available IPs manually. Also on the MACbook don't use DHCP, but manually enter a fixed IP outside the DHCP range of the Fritzbox.

Thank you for your prompt reply!

I have set the IP address for a long time. Since the Fritz! Box only reassigns the IP addresses every few weeks and nothing appears in Log, I can hardly imagine that it has something to do with it.

It was just an idea, DHCP negotiates, fixed IPs without DHCP - nothing negotiates there. If this would work.

If, as I said, no DHCP is effective for this connection on both sides, the cause would not be eliminated, but the symptoms may be.

Vodafone?

No, we're at Netcom.
But it can't really be because of that: as I said, the problems do not occur on the PC with a patch cable.

I often read of such problems with Wi-Fi devices that supposedly briefly disconnect the Wi-Fi connection every 5-10 minutes (according to the router LOG) and then immediately reconnect (as a result, short interruptions on the Wi-Fi client).

I personally suspect

band steering (automatic change between 2.4 and 5 GHz)
or the Mesh (automatic change of WLAN access point = WLAN roaming).

So it could be a software error in the router and / or repeater. Make sure to install Fritz updates!

I would still make the suggestion with the fixed local IP addresses (from @CatsEyes). Because it is also mentioned here as alleviating the problem: https://www.tutonaut.de/probleme-mit-fritzbox-mesh-hier-ist-die-loesung/

So on the configuration page of the DHCP server (= the FritzBox) in the network settings for the "problem device", activate the setting "Always assign the same IP address to this WLAN device".

Please give me a short feedback if it can be shown to have helped.

Thanks for the support!
I checked that and made sure that the device has a fixed IPv4: unfortunately without success. MacBook continues to merrily reconnect every few minutes.

About the mesh: currently I only have the Fritz! Box active; all other repeaters / APs are switched off. Regarding band steering: If band steering occurs (rarely), the Fritz! Box log explicitly states that a device "was switched to another frequency band to improve the transmission rate"; that's never the case with the MacBook.

Mobile devices (e.g. Cell phones) reconnect more frequently when moving through the house and change the frequency depending on the distance. But then it is explicitly stated in the log that the device has "re-registered" together with the frequency change.

Neither is the case with the affected laptop (MacBook). The log says "WLAN device has been logged off" and a few seconds later "WLAN device has been logged in"… Quite strange.

Thanks for this good information.
I've put your question on my watchlist, if I should ever find out what is causing the MacBook to behave like this, I'll let you know.

PS:

Personally, I have set different SSID'S in my FritzBox 6490, also my 2 other access points I have missed other SSIDs, because earlier (~ 3 years ago) different Samsung smartphones were messing with band steering.

Since I switched to different SSIDs, I haven't had such inexplicable Wi-Fi problems with Samsung (tablets and smartphones) or iPads. I'm satisfied and do without these "mesh" marketing bells and whistles, because nothing is more annoying than unstable network connections.
I leave this WLAN switch decision to the WLAN clients, the clients (tablets and smartphones) also switch independently if the WLAN signal becomes too "thin", that's enough for me.

Thank you very much!
I once deactivated the band steering - unfortunately without success. The MacBook is a few meters from the Fritz! Box removed, there's no further AP or repeater in the mesh, but it briefly disconnects every 5-10 minutes.
I also wrote to AVM once; as soon as I get an answer, I'll post it here.