unable to login to nwa or ume

Hi,

Our ABAP+JAVA system is working fine, I can see all the green lights in MMC. I can login to ABAP clients successfully. But I can't login to nwa or UME (useradmin). The user credential screen opens which means j2ee is working. But when I try to login using j2ee_admin user the system gives an error "Authentication failed. Logon with password not allowed" and If I try to login using any other user with same authorization as j2ee_admin the system doesn't give any message or error message. It just refreshed the screen.

Please let me know what is the issue? Yesterday we were able to login but today we can't

Regards,

Sudip