Snom D735 loses registration

Hi

i try it in english now. and hope to get help.

If not, I guess, i have to buy another phone and bring this back to the shop.

I have connected the Snom D735 firmware version snomD735-SIP 10.1.169.15 (same Problem wit snomD735-SIP 10.1.169.13) hardware version1 to a Fritzbox 7590 SW version 7.57. Configuration was quite simple.

Configuration was pretty easy. Apart from login data, nothing changed as far as SIP telephony is concerned.

I have registered 4 numbers. These fail at least once a day. Registration is no longer possible. Access via browser no longer possible.

Only after restarting (de-energising) the phone does everything work again until the next registration problem.

What do I need to supply?

Greetings, Jörg