I am registering my client to kamailo successfully. client --> Register --> kamailioclient <-- 401 with nonce value <-- kamailioclient --> Register with nonce and md5 response values --> kamailioclient <-- 200ok <-- kamailio However, when the client sends an invite with the same digest values, kamailio sends a 407 request for another challenge: client --> Invite with the same nonce and md5 response values --> kamailioclient <-- 407 <-- kamailio I am thinking the same digest values from register could be used for making calls. Thanks,Al