MSRMaps.com (source of the 'Topo', 'Aerial' and 'Urban' tiles) is giving a 'too busy' message today.
TF is unable to download maps and will give a 'having trouble contacting server' message. Most likely this will be a short outage.
If you're a registered used, you may wish to download the current beta, or inquire about it. It features an alternate topo server.
