[Users] ser doesn't anwer to that request...

Hi there, Strange beahvior or I am Blind... This phone try to register and ser doesn't answer with a wwwauthenticate, doesn't answer at all in fact... all ideas are welcome :) Olivier U 213.219.xxx.xxx:10002 -> 82.146.xxx.xxx:5060 REGISTER sip:82.146.xxx.xx SIP/2.0. Via: SIP/2.0/UDP 213.219.xxx.xxx:10002branch=z9hG4bK8fb09b20aace531cb21a1abd57c0957d;rport. From: Astel.be Greg <sip:995045099@82.146.xxx.xx>;tag=3528839207. To: Astel.be Greg <sip:995045099@82.146.xxx.xx>. Call-ID: 705145430@192_168_2_2. CSeq: 1 REGISTER. Contact: Astel.be Greg <sip:995045099@213.219.xxx.xxx:10002. Max-Forwards: 70. User-Agent: Siemens Gigaset C450 IP. Expires: 180. Allow: INVITE, ACK, CANCEL, BYE, OPTIONS, INFO. Content-Length: 0. .