Source System - RFC Connection

From RSA1 if I go to a source system in B/W, right click and choose the check option, I get an error message which says BW Unknown in source system. I think this is indicating that the RFC is not set correctly. I have gone to another B/W which also accesses the same Source System and have done a check and the connection is fine.

If I right click the Source System and select Change in both B/W systems everything is identical except the name entered for the Target Host. If I ping both names the IP address is identical though. Would the Target Host name cause an issue? If not can someone advise on the steps to fix the RFC? Thanks