Is this the full stack trace? I also had timeout problems, but in my case the error also contained an HeartbeatException in the Servers list of the error message. So I doubt it is the same problem. In my case it was the problem with using IPv6, for which I wrote the GetIPv4Host function, are you using that?
You could also check Error Handling in the drivers reference.
You could try playing around with your connection string to see if you can find a solution with settings, depending on how your MongoDB is configured, like here.