Password reset error " This system does not let you to log on using password"

Dear Experts,

I have created one custom appl'n which helps user to reset/unlock the password in selected system.After go-live in PRD system, Only for few user's it is giving error " This system does not let you to log on using password" when they try to reset the password.

For password reset, Im using CL_GRAC_AD_ACCESS_MGMT=>RESET_USR_PWD( ) in GRC system. I've checked the field BCODE in USR02 for that user, It is not NULL. Pls help me to resolve the issue.

Thanks

Katrice