asterisk users - Jan 2006 - Problem with Vonage and Asterisk, Please help me

Hi All,

I installed Asterisk and trying to configure Vonage with it. After getting
authenticated when I try to call to a number I get the following errors

First I get

Sip read:
SIP/2.0 407 Proxy Authentication Required

CSeq: 104 INVITE
Proxy-Authenticate: Digest realm="216.115.20.41",
domain="sip:216.115.20.41",
nonce="365527150", algorithm=MD5
Max-Forwards: 15
Content-Length: 0

Jan 18 10:40:48 NOTICE[5624]: chan_sip.c:6884 handle_response: Failed to
authenticate on INVITE to '"16082376967"
<sip:16082376967@216.32.80.226>;tag=as20c657ec'

Please help me and let me know my mistake.

Thanks,
Manoj