[Users] Problems with digest authentication

I have been using various versions of SER from last year without any problem but recently I made a new installation of OpenSER 0.9.5. Since then I am having problems with digest authentication from some of the phones. I have a bunch of 186 ATAs and Cisco 7940 phones but they cannot register to the server, while all the soft phones can register successfully. The server says Credentials with given realm not found. I tried to change the realm to localhost and to the the IP address of the server, with no luck. And below is the result of ngrep I tried to grep the messages from the phones and here below is one message from a Cisco 186 ATA which has failed to register ########### Beginning of the capture ################## U PHONEIP:5060 -> SERVERIP:5060 REGISTER sip:SERVERIP SIP/2.0. Via: SIP/2.0/UDP PHONEIP:5060. From: <sip:06090003@SERVERIP;user=phone>;tag=500808430. To: <sip:06090003@SERVERIP;user=phone>. Call-ID: 704382462@PHONEIP. CSeq: 1 REGISTER. Contact: <sip:06090003@PHONEIP:5060;user=phone;transport=udp>;expires=3600. User-Agent: Cisco ATA 186 v2.16.2 ata18x (030829a). Content-Length: 0. # U SERVERIP:5060 -> PHONEIP:5060 SIP/2.0 100 Trying. Via: SIP/2.0/UDP PHONEIP:5060. From: <sip:06090003@SERVERIP;user=phone>;tag=500808430. To: <sip:06090003@SERVERIP;user=phone>. Call-ID: 704382462@PHONEIP. CSeq: 1 REGISTER. Server: OpenSer (0.9.5 (i386/linux)). Content-Length: 0. Warning: 392 SERVERIP:5060 "Noisy feedback tells: pid=4490 req_src_ip=PHONEIP req_src_port=5060 in_uri=sip:SERVERIP out_uri=sip:SERVERIP via_cnt==1". # U SERVERIP:5060 -> PHONEIP:5060 SIP/2.0 401 Unauthorized. Via: SIP/2.0/UDP PHONEIP:5060. From: <sip:06090003@SERVERIP;user=phone>;tag=500808430. To: <sip:06090003@SERVERIP;user=phone>;tag=329cfeaa6ded039da25ff8cbb8668bd2.8af0 . Call-ID: 704382462@PHONEIP. CSeq: 1 REGISTER. WWW-Authenticate: Digest realm="talk.artel.rw", nonce="42edb29e1dbcc6fa814dd3396634ed7be68eea56". Server: OpenSer (0.9.5 (i386/linux)). Content-Length: 0. Warning: 392 SERVERIP:5060 "Noisy feedback tells: pid=4490 req_src_ip=PHONEIP req_src_port=5060 in_uri=sip:SERVERIP out_uri=sip:SERVERIP via_cnt==1". Any idea? Aimable