Facing issue with PPP authentication failure to UART bearer

bearerRet = wip_bearerSetOpts ( br,
/WIP_BOPT_LOGIN, PPP_USER,/
/* WIP_BOPT_PASSWORD, PPP_PASSWORD,*/
WIP_BOPT_PPP_PAP,FALSE,
WIP_BOPT_PPP_CHAP,FALSE,
WIP_BOPT_END );
I disabled both PAP and CHAP authentication but still i am facing issue WIP_BERR_PPP_AUTH_FAILED. Please give me some suggestions i am in critical because i am facing this issue last 1 month.
Thanks.

-Ganesh