Here is the list of common problems while starting web server

- Could not bind port (Port already in Use)
- found .pid file ( When Apache starts it creates .pid file in logs directory and when you shutdown apache it cleans this .pid file so if this file is already there then Apache will not start. Fix: Simply move this file
If there is no error messages in error_log or error_log_pls then there might be issues in starting Jserv component of web server ( which caters Java requests by mod_jserv)
- mobile is enabled in zone.properties disable it if you are not using it .

If you mistype any directive in Apache ( httpd.conf or any conf file ) Apache will not start & it will not write even in error_log in that case it will report any error message related to mis configuration in directive in file $COMMON_TOP/ admin/ log/ $CONTEXT_NAME/ adapcctl.txt

I hope once you have error message you can check related hits in metalink or oracle forums or any other Apps Forum. Most of the error message are because of changes , so check what changes you made recently.

Once you are able to access http://hostname.domainnameort and if you are getting any error message that means your web server is working but there are various component called as modules and there may be issues with those modules which we will check these modules in next post. few modules of our interest are
-mod_jserv
-mod_pls
-mod_oprocmgr
-mod_ossl (If you have ssl enabled on web server )
-mod_osso (If single sign on server is enabled on web server)

If you donít know port number of your web server you can check it in file $IAS_ORACLE_HOME/Apache/Apache/conf/httpd.conf with directive Listen & Port.