I'm afraid this is not a Rebex issue. If this occurs often, it means that something is wrong with your machine's network connectivity.
The error comes from the operating system's TCP subsystem and indicates that an attempt to connect to a TCP endpoint failed because no response was received from it within the allocated timeout interval (which is a system-wide setting).
On windows, this error corresponds to Windows Socket error WSAETIMEDOUT (10060):
Connection timed out.
A connection attempt failed because the connected party did not properly respond after a period of time, or the established connection failed because the connected host has failed to respond.