The Proxy Adapter waits for the connections by the Remote Adapter in sequence. Therefore, the ports are not open for listening all at the same time:
the 6663 port is opened for listening first;
after the Remote Metadata Adapter has connected, it is closed for listening;
then the 6661 and 6662 ports are opened for listening;
after the Remote Data Adapter has connected, they are closed for listening.

Until a port is open for listening, the Server is blocked and the last line on the log says:
"Connecting...".

Is what you observe still different?

Dario