Problem with Nokia E70 answering from ringing group

[arpa]

I have problem with Nokia E70 , when a digital receptionist connects to a ringing group. When I try to answer from my Nokia, the phone reboots. I have no problem , when i call directly to the phone's extension, or when i call the ringing group where the specific extension belongs to.

Any idea , or better, any solution...

 

[arpa]

I have uncheck the "Supports Re-Invite" option (Extension number/ Other options), and now seems to be ok.