3g modem chap authentication error: peer refused to authenticate: terminating link

["X.H. Sheng" <xhsheng gmail com>]

Hi,

I got the following error message when I tried to use chap-secrets file to do pppd connection

"peer refused to authenticate: terminating link
Connection terminated."

Anyone knows why this happen? In addition, I have more confused about chap-secrets authentication. When I read those SIP/MIP documents, it says: Chap authentication is using random number dynamically generated by the server to do authentication, and there is chap-id etc. However, in pppd, we put the fixed secrets(password, usually it's text words) in the chap-secrets file. Does it mean "the chap-secrets authentication for pppd"  is different from  "SIP standard chap-authentication"? Or they are totally two different concepts?

thanks 

Xiaohong