Hi Indrajith,
For the 404 error, simulate this issue and get httpwatch trace following note 1558903. Then attach trace as .hwl file to this thread.
You can use below way to test SSO from EP to ABAP.
1. Log on EP with user and password, make sure same user ID exist in ABAP system.
Make sure you log on EP with FQDN of EP server.
2. Replace URL with URL of ABAP ITS URL, then access it. Of cause you need to make sure this service node is active in ABAP via t-code SICF.
For example:
http://<FQDN of ABAP server>:<ABAP ICM port>/sap/bc/gui/sap/its/webgui?sap-client=<client number>
**Replace <client> with the ABAP client number you want to SSO to.
3. If you see log on page of ABAP system this means SSO fail, otherwise SSO is working fine.
Hope this could help you!
Amy