T24 does not stop SIP signalling after door opened, Fritzbox DECT phones still ringing

I had a very well working config with a T24 door station & door opener connected to a Fritzbox, which is also the DECT Server. After a crash (please don’t ask me, what happened), I had to reset everything to factory settings. Then I was asked to update the firmware…perhaps not the best idea…
In the meanwhile everything works again, except:

  • Someone rings the doorbell, signalling starts, the SIP phones ring…but when someone opens the door, the phones don’t stop ringing, and I don’t find the right settings to end the signalling (I checked at the door opener, the blue light stops flashing, when the door is open)
  • opening the door does not work anymore…pressing the button at the door opener for 3s makes a little bit noise at the door lock (not as loud as it used to do) and at the door opener I hear a very gentle buzz.
  • the video quality got so bad after the firmware update, especially in the evening/night, it is nearly unusable

I appreciate any hint…

Cheers, Henning

to one of the moderators: can you please remove the ‘how to:’ from the heading? This is misleading as I am looking for help and don’t want to give advise…sorry for making the title so irritating…
Thanks, Henning