[SR-Users] Failed auth

Hello! I have kamailio 5.0.5 and some cisco spa 50x phones. Sometime phone can't register to kamailio. REGISTER packets with right nonce,reponse, etc gets to kamailio but it response 401 Unauthorized with code -3 (user not found). After some attempts(or time, phone send register every 1200 seconds) or after reboot phone it register succesfully Feb 13 11:20:02 sipchel /usr/sbin/kamailio[110432]: NOTICE: <script>: AUTH: REGISTER [a470211a-b7d8faa5(a)172.16.3.1] Feb 13 11:20:02 sipchel /usr/sbin/kamailio[110432]: NOTICE: <script>: AUTH: REGISTER FAILED (code: -5) fd=voip.xxxx.org, adu=<null>, aa=<null>, ar=<null>, au=<null>, ad=<null>, aU=<null>, Au=33855(a)voip.xxxx.org [ a470211a-b7d8faa5(a)172.16.3.1] Feb 13 11:20:02 sipchel /usr/sbin/kamailio[110433]: NOTICE: <script>: AUTH: REGISTER [a470211a-b7d8faa5(a)172.16.3.1] Feb 13 11:20:02 sipchel /usr/sbin/kamailio[110433]: NOTICE: <script>: AUTH: REGISTER FAILED (code: -3) fd=voip.xxxx.org, adu=sip:voip.xxxx.org, aa=MD5, ar=voip.xxxx.org, au=33855, ad=, aU=33855, Au=33855(a)voip.xxxx.org [ a470211a-b7d8faa5(a)172.16.3.1] Feb 13 11:20:02 sipchel /usr/sbin/kamailio[110431]: NOTICE: <script>: AUTH: REGISTER [a470211a-b7d8faa5(a)172.16.3.1] Feb 13 11:20:02 sipchel /usr/sbin/kamailio[110431]: NOTICE: <script>: AUTH: REGISTER FAILED (code: -3) fd=voip.xxxx.org, adu=sip:voip.xxxx.org, aa=MD5, ar=voip.xxxx.org, au=33855, ad=, aU=33855, Au=33855(a)voip.xxxx.org [ a470211a-b7d8faa5(a)172.16.3.1] -- Aydar A. Kamalov