In our Project we were facing lot of issue while configuring FPN between BI producer portal and Portal Consumer .
Finally the issue is resolved but here are some tips i want to consolidate which can help to fix the issue :-
1.We correctly configured SSO between BI producer portal and Consumer
Then also we were getting below error while registering fpn :-
com.sap.security.core.persistence.remote.CommunicationException: Sending request to connection 'bi-finscm_portal' has failed. Please check attached exception.: javax.xml.soap.SOAPException: SOAP Response Message was not well formed (java.net.SocketTimeoutException: Read timed out).
at com.sap.portal.ivs.global.roles.RemoteProducerAccessImpl.sendToRemote(RemoteProducerAccessImpl.java:545)
We tested SSO , network connectivity between both portal .
Then finally we found below RCA
According to the following SAP Note 1718291 (Consumer Portal availability when producer Portal is down) the configuration of the 'SOAPCallTimeout'
parameter should be set to 30000 milliseconds (30 seconds) and it was
set to 30 milliseconds (0.03 second) in our system. There for we
always get a timeout error when we try to reach the producer host.
We configured the parameters and necessary steps as suggested in SAP Note 1718291.
Configured FPN and it worked .
Please share your experience also on FPN configurations 
Regards,
Abhishek