This error is caused by changing the branch of the license to another branch, make sure that all data has been uploaded to the console, in case there is data that has not been uploaded to the console, reassign the license to the old branch, then activate the app and tap on Sync Data.

Then follow these steps:

1. Delete the app and download it again from the App Store.
2. After the download is complete, tap on the app icon, and then tap on the Start button.
3. After that, a new screen will appear. Enter your Account Number in the field above and the Cashier Code in the lower field.
4. Tap on the Activate button.

To get the cashier code:

1. From the console, click on Manage.
2. Click on Devices.
3. Click on the required device license.
4. You can use the green code to activate the app.

Note: If the code is red, press on Deactivate Device.