FNP - Between EP 7.0 - CE 7.2

Hi Experts

I try to configure a FNP, when I create a producer object in the consumer portal with the hostname or FQDN results in this error: Producer object was found

could not retrieve the WSDL file; the handshake URL may not exist or may be invalid. But if I do the same whit the producer portal IP the test result ok, SAP recommend not use the IP. You could tell me how I can resolve this problem?

This is some important information

Consumer: EP 7.0

Producer: CE 7.2

SSO is working fine.

Hostname and FQDN are registered in the hostfile.

Thanks.