If you're on a PC, this is usually something blocking the exe from reaching the Internet.
- Make sure your firewall and antivirus are not blocking SimCity.exe, and that it is added to the exception lists. I know when mine updates, it occasionally likes to change settings for no good reason. If you have BitDefender installed, disable it.
- If you have any mods installed, remove them
- Make sure your graphics drivers are updated to the most recent version. If you have the sound program Nahimic 2 from MSI installed, disable or uninstall it.
- Set the desktop icons to run SimCity.exe and Origin.exe as administrator
- In Origin, right-click SimCity icon, Game Properties, check the box that says "Disable Origin In-game"
- Set the SimCity desktop icon to run in Windows 7 or 8 compatibility mode.
If none of these work, try a clean boot and attempt to launch SimCity. If it launches, you'll have some detective work to do, enable one startup program at a time, reboot, try SimCity, until you find the program that is blocking it.