As the last post regarding this issue was from 3 years ago, I figured I'd give an updated and working solution in case someone else is having this problem. I have been struggling with this for the last 2 years or so. Every time I would launch the game, it would pull up a little grey window that said: Invalid license. Reason code=Invalid Cipher(0x0006) and close is the only option.
The only fix from what I could find is to use the SimCityRecovery.exe file. But when you launch that it takes you to a Help.EA.com page that says: Sorry, that page doesn't exist! According to others, it used to provide a tool that would help. Eventually, the support for SimCity was cancelled and the page just said that the tool is no longer supported and the recommended fix is to uninstall and reinstall the game. I have done this many many times, around 15. Each time it would only give me the same problem: Invalid license. Reason code=Invalid Cipher(0x0006)
I finally broke and contacted tech support about it. It took a lot of explaining (and about 3 hours) but I eventually got a solution that worked.
1. SimCity has to be installed currently
2. Get the free version of Revo Uninstaller (link below).
3. Run it and let it load all your programs.
4. Select SimCity and hit uninstall.
5. It will uninstall it like normal but then it gives you an option to search further for more files. Use the Advanced option. It may take a few minutes as it's searching your entire hard drive for anything SimCity related.
6. Select every file that says SimCity. Just the files that say SimCity NOT the branch of folders and subfolders.
7. The next page is any folders that are associated, delete those as well.
8. Reinstall the game.
After all that it finally worked for me. Make sure you have an internet connection when you launch it for the first time as the launcher will need to update for a few minutes.
I played the game multiple times now without a problem. Due to the lack of support for the game, this will probably be the only fix for most things. Regular uninstall and reinstall or using Revo uninstaller. But at least for now, there is a working solution.
Here is the link: https://www.revouninstaller.com/revo_uninstaller_free_download.html