I did a test with a Pycom WiPy 3.0 - it will also not connecting on the Vodafone Station :(
It seems that some routers have issues, when connecting an ESP32.
In the next days I am testing an Arduino sketch, instead of MicroPython.
@plusulli : This is good to know, but this is not the solution for this problem :)
Anyway, I bought now a repeater "tp-link TL-WA854RE" from Aldi Süd. The repeater connects without problems on the Vodafone Station and the M5 devices works with firmware 1.6.0 on this repeater. So I have an workaround for now, but I hope for a real solution ...
this is a problem on all M5 Devices with firmware >188.8.131.52! I have test it with M5Stack Gray and M5StickC.
I get following message on the COM monitor on router Vodafone Station:
 MQTTException -> [Errno 113] EHOSTUNREACH
reconnect start ...