If possible, connect the Windows machine to the build host over a wired internet connection, or improve the wireless connection to reduce latencies and packet loss. The Mac build host connection is not currently designed to be robust against latency and packet loss.
In theory, advanced setups that use traffic shaping for the network might also cause observed packet drops, but only if the particular packet filtering rules apply to the communication between the Windows machine and the Mac build host.
Long delays when attempting to connect to the Mac build host
Some reports have indicated that the connection process can take as long as 20 minutes in problematic setups.
Time outs in the Mac Server Log in Visual Studio
Server returned an error. The request was aborted: The operation has timed out.
Time outs in
~/Library/Logs/Xamarin/MonoTouchVS/mtbserver.log on the Mac build host
Error: Failed to acquire command execution lock, the request timed out (00:10:00)