Problem: Failed to attach to the relay server with the message "<rshost> failed to attach to Relay Server 'ias_relay_server_host' shared memory."
Explanation: This message may appear if you try to update Relay Server configuration using the command rshost.exe -u -qc -f rs.config.
Solution: Remove the -u option, since the server is not up and running. The -u option updates the configuration of a running relay server.