R12 Blank Login Page

This may happen some times, mainly after the clone or even after some bounce.

There are multiple options to check, and try:-

1. The first thing you need to check always is DB is running fine.
   In case you are are not aware then I must tell you, its better to check if "apps" user is working fine.
2. One more thing you should check is the Alert Log, as there may be issues related to Database.
3. Later comes the Apache logs. Location is "$LOG_HOME/ora/10.1.3/Apache".
   The files are error_log and access_log, check the latest ones.
   And if that looks OK.
4. Go for a clear cache bounce.
   Well in R12 clear cache bounce means clearing the file from -pages directory, and regenerating the .jsp
   Below link may help you with the process of clear cache bounce at R12.
   http://tk-appsdba.blogspot.com/2011/01/clear-cache-bounce-in-r12.html
5. And in addition to that we can clear the persistence too. For that :-
   Delete or move the files under below directories $INST_TOP/ora/10.1.3/j2ee/oacore/persistence
   $INST_TOP/ora/10.1.3/j2ee/oafm/persistence
   $INST_TOP/ora/10.1.3/j2ee/forms/persistence
6. Now restart the services and retest the issue.