Limited internet connections tplink deco in guest mode with pihole DHCP

[remc]

I have a problem with tp-link deco's, and limited gateway connections via guest network.

Setup: My I have a raspberry pi with Pihole als my DHCP.
My ziggo modem is in bridge. Also I have a TP-LINK Deco M4 mesh wifi setup, in AP mode. I work with switches in between .

On the TP-link DECO i run a main wifi network (2.4 / 5 GHz) and a guest network (2.4 GHz)
Because the deco is not the dhcp server, the guest network runs on the same IP range (not really a seperated lan).

On my guest network i have ca 20 devices connected , like smart plugs, IOT, but there seem te be a limit somehow. When I connect another device to the guest network, I don't have internet. (also devices that had no problems in the past)
.
I do get IP adres, mac , gateway etc.
I am connected in the deco app, but I don not have internet.(while other connected devices do have internet via the guest netwotk)

When connect the device to the main deco wifi network, I suddenly do have internet connection...

Could this be caused be a setting in the pihole DHCP? (like max gateway connections _),

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Also I experience sometimes that my network (including wired network) is not responding anymore.
and the only fix is a reboot of pihole, with the tplink deco-master powered off. Like ithe deco's sometimes suddenly go back into router mode and wants to take over the network or somehing? I was not able to check that, because pihole IP is not reachable at that moment...

[rdwebdesign]

This is a guess because I don't use TP-link DECO device, but maybe your issue is related to device isolation and devices are not able to use Pi-hole IP as DNS server.

Using Device Isolation on Deco

[remc]

No that's not the case. Devices that worked before, failed on reconnect. I renamed SIDD and back to original, restarted so the IP lists was renewed
Devices that worked before, where now back connected, but no internet. Other devices that didn't communicate, where now connected with netwok AND internet,

TP-link support suggested that the DHCP server could not communicatie in a proper way...So that resulted in my post here, Maybe there is a setting or max value i need to change..

I disconnected my TPlink Deco guest account., and activated the guest wifi at the ziggo connectbox, with still pihole as DHCP . All my problems dissapeard at once..All devices (in range) connected without problems...

So there seem to be a limitation in the TP-link deco mesh system...