This is such a frustrating error. It's almost always due to some corruption caused by interruption from the client to the server on exit/save. Probably not a problem on your end, but on the server side, unfortunately. People have not seemed to have a lot of luck recovering from this, back when the game was new and it was happening all the time, I believe they asked for the information you provided and went through and tried to troubleshoot or roll back cities where it was happening. I don't know if they are doing the same now, though.
Some basic things - If you installed any mods, delete them. Reboot your machine to make sure there are no processes running in the background.
Here are some things to try, I hope one of them works:
1. Go into a city in the region that does load, then go to region view and see if you can load the problem city from there.
2. Make sure your firewall and antivirus are not blocking SimCity.exe, and that it is added to the exception lists. If you have BitDefender installed, disable it.
3. Run SimCity as administrator
4. In Origin, right-click SimCity icon, Game Properties, check the box that says "Disable Origin In-game"
5. In Origin, right-click SimCity icon, choose "Repair Game"
6. Run SimCityRecovery.exe Default location is \Program Files (x86)\Origin Games\SimCity\SimCityRecovery
7. Delete everything in the SimCityUserData folder and load the game again. (Program Files (x86)\Origin Games\SimCity\SimCityUserData)
If none of the above works, you could try calling support to see if they can roll back your city. Otherwise, you may have an unrecoverable city. Good luck!
