GL-MT300N-V2 3.212 adding new WIFI Device disconnect all other

I Use the Mango in “Router” Mode.
Internet is connected by Wi-Fi / Manual DNS / IGMP Snooping On.
I have already at least one device connected (device A) by Wi-Fi.
Then I want to connect a new device (device B) by Wi-Fi.
The new device B connects well, but all other devices (A) will be disconnected!

Any Idea? Please help :slight_smile:
Thanks in advance
Oliver

Can you get the system log?