Fingerprint scanner not working after replacement

Replaced screen on google pixel 6a. I'm aware some say it needs recalibrated, however I had a plus sticker looking thing on the back of where my scanner is when the screen was off for replacement. It didn't feel like It would come off, is that suppose to be on there? If I click the button on side of phone that pulls my screen up, where the finger print icon would normally be it flickers fast between that and a lock icon. Is this just saying it needs recalibrated? Thank you