How do I fix 'Connectivity Failure. Check Connection'?

This error message comes up when ASGS cannot connect to the server. This could happen for a few reasons:

• Make sure your internet connection is working. Try loading a webpage to see if you can access it.
• Make sure no software firewall (or antivirus program) is blocking ASGS or Allegiance. (Disabling the firewall or AV "network shield" is often insufficient; you may have to uninstall the firewall or AV program to identify it as the culprit.)
• Make sure Internet Explorer is "Working Online". Even if you use Firefox or Opera, Internet Explorer must be in "online" mode
  • Launch Internet Explorer
  • Click the "File" menu
  • Ensure there is no checkmark beside the "Work Offline" menu item
• Check Windows Update for any updates to Windows.
• Try changing ASGS's connectivity mode:
  • Launch ASGS
  • Click the File menu
  • Click Connection Port and note which of the two options is currently checked
  • Click the option that does not have a checkmark to change the port