Connection Managers use a specific port to connect to the server. The port to use is specified in conf/manager.xml. However, ConnectionWorkerThread is doing a DNS SRV lookup to find the actual IP address and port to use to connect to the server. The problem is that the DNS SRV lookup is a s2s lookup thus port 5269 is going to be returned thus overriding the CM port.
We just need to do the DNS SRV lookup to find the IP address and ignore the returned port.