If you're on Windows I think that's a bug they're still working to fix. If you're on any other platform I'd suggest connecting Township to Facebook/Google to save your town then re-installing it. For a quick fix you if you've already connected with Facebook/Google you can delete the app cache and data in Settings > Storage > Township.
Edit: If it's still not working contact Playrix through the in-game help topics. Just select the main topic you're having an issue with then select "No" when it asks if the information helped.