Broken pipe to reverse invoke gateway

I have an internal and reverse invoke IS 7.1.3 with all of the current fixes applied (up to Core Fix 15). The registration port on both servers is configured to use certificates only for HTTPS. The HTTPS registration ports on both servers are active, but immediately after the internal server comes up, it issues the following msg:

Unable to establish connection to the Reverse Gateway server, Exception → Broken pipe.

The Reverse Gateway server has a persistent connection from the internal server (I can see it using netstat), and there is a firewall in between the 2 servers. But so far nothing on the firewall configs points to it causing a problem.

Has anyone else seen this message with IS 7.1.3 in a reverse invoke setup? Can I do anything to prevent it?

Did you try sending a request from the RI servers to the back end servers to see if the request were getting provisioned.?