For anyone who may be having connectivity problems with the new sim, it could be down to your router not having the correct ports open. You may have been through this before with FS2004, FSX, or P3D. We covered this topic when the old FSX Gamespy multiplayer service was terminated and we all had to connect directly. Jess wrote a guide at the time here ..
Here's a brief summary.
Before you can forward a port you need to know the following things:
Your router's IP address.
Your FS machine's IP address.
The TCP and UDP ports that need to be forwarded.
IP address