EBS-- adadmin and adpatch use APPLSYS account, too..

While using adadmin or adpatch, if you encounter invalid user/pass error like the below, check APPS and APPLSYS account status.  You can encounter this error not only because of the APPS account but APPLSYS  account, which owns the Application Object Library, too..
Acutally adadmin wants password for APPS if you read the prompt , so It s kind of  misleading :)

Enter the ORACLE password of Application Object Library [APPS] :

AD Administration is verifying your username/password....Unable to connect.


In this situation, check apps and applsys account using sqlplus and verify the account status..

sqlplus apps/apps_pass
sqlplus appslsys/applsys

Or use the below to identify the locked Apps accounts;

select USERNAME, LOCK_DATE , from dba_users where USERNAME like 'APP%';

This problem can arise mostly after a password change operation for APPS account..

Sometimes because of the wrong the procedure and sometimes because of the db profile options, this problem can be reproduced.. 

An example for the effect of FNDCPASS -> The cause can be the fact that the FNDCPASS had failed several times due to the Rollback segment issue and had locked the APPLSYS account

An example for the effect of db profile options -> third party applications have tried the old apps password and made the apps/applsys account blocked, because the relevant db profileoption has a limit for the failed passwords..