Fingerprint sensor not working correctly after screen replacement

Hey guys.

Just replaced my first one of these & I took extra special care when I got to the home button assembly.

I thought all was well but customer has just contacted me its not recognising finger prints.

Normally when home button is damaged you get Touch ID not working or failed message but I got none of that client face timed me to show me & they can go into Touch ID & passcode & add fingerprint they even get to the place finger on button part with the blank fingerprint but when they touch it on nothing happens normally you would get the red lines as it adds the fingerprint but they’re getting nothing.

Any ideas guys cheers?