Nowadays, most people restore their apps from old to new phone.
If this is the case then SecureIdentity app will not work.
This is a security app that hold your digital identity. Backup and Restore will not work.
Delete the app and go to Play Store or App Store and download the up-to-date secureidentity app.
Open a browser and visit https://secureidentity.co.uk/ - select My Account - click on Changed Mobile -then follow on the screen instructions.
Ideally you should use a dual device option; one to start the browser session and the other (mobile device) to download and set up the secureidentity app on it