An old Snom-190 phone looses reg after 30 seconds

Our office uses Snom-320 phones which are fine, but I also have Snom-190. It is EOL and end of support also. Never-the-less it used to work with Asterisk-1.xx. It does not work anymore with Asterisk-11.4.

It registers fine and can receive and place calls for a total of exactly 30 seconds. After that it looses the registration. It’s log shows that 'Registrar refused with code 401"

It looks like the Snom-320 also get that, but instead of loosing the reg, they put a warning entry in the log “process_registrar_packet: 401 needs 128 bit nonce”, which makes me believe that Snom made the firmware to simply ignore the response from Asterisk instead of reacting to it. Obviously Snom-190 does not have a firmware new enough that that is implemented. I just wondering if there is a workaround this on the Asterisk side.

I did try disabling “Challenge Response” in the phone, to no avail.

I can simply sling the phone in the trash, but if I can get it to stay, It is a pretty slick and simple set that I like a lot and can give it another life in the office. Thanks,