@JaydenTheYT4 wrote:
do Russian letters count?
Yes, Russian letters could cause an issue. Try renaming any cities that use them. (you can change them back after it transfers) If you have any mods installed, remove them. Temporarily disable antivirus and antispam software while you're trying to transfer the region. Make sure you set your Origin and SimCity icons to "Run As Administrator" (right-click, choose properties, compatibility tab).
Delete all the files in \Program Files (x86)\Origin Games\SimCity\SimCityUserData\WebStorage\LocalStorage and \Program Files (x86)\Origin Games\SimCity\SimCityUserData\EcoGame and try again. (You can just remove the entire SimCityUserData folder if you want, when you log in again the game will update it again. Do this after you rename any cities - log out, delete the folders, then log back in and let it put the folder back in, then try the transfer again)