If you delete the app without authenticating your account, your current progress in the game will be lost! Unfortunately, there is no way to recover an account if it has not been authenticated.
1. Delete Stronghold Kingdoms
2. Reinstall the App and select - 'I am an existing user'
1. With Stronghold Kingdoms installed
2. Select Settings
4. Stronghold Kingdoms
6. Clear Data
7. Start Stronghold Kingdoms and select - 'I am an existing user'