LSO Publish Course, Connection to backend system failed.

Hi Experts,

When I try publish course in Publish Course Content windows, I see in the Content Management this error

Connection to backend system failed. 

As already we have rechecked on the following activities:

1. RFC Connections and SSO configuration in ECC and Portal systems, RFC connections are working fine.
2. Maintenance of HTTP RFC destination PORTAL in visual admin tool

3. Checked all the authorizations related to communication users
4. Analyzed the trace file, cannot find any information with reference to this issue

But problem still persist, Please help me on this

Your responds will be appreciated.

Thanks & Regards,

Vamshi Krishna