Can't connect to any sites

After not having trouble for years, I cannot connect to any sites today (I have shut down and restarted my computer in case). I get the same message (three lines ending in the "Connecting to...") and then it just hangs -- no error, no log off, no connection.

[05:56:55] SmartFTP v2.5.1008.5
[05:56:55] Resolving host name ""
[05:56:55] Connecting to Port: 21

It seems another application installed on your computer is blocking SmartFTP from making a connection. Typically the application in question is a software firewall or antivirus product. Add SmartFTP to the exceptions in the application's settings and try again. If this doesn't work temporary uninstall your Antivirus and Software Firewall products.