If you were able to install the Libre 3 app on your Android phone that likely means your phone is compatible with the sensor, here are a couple things to try to help you to get the sensor to scan.

Make sure you have hit the "Next" button and the screen says "Scan new Sensor" and the button is greyed out and says "Back"

NFC Location "where you tap" your sensor is typically located on the center back of the Android phone.

Most cases should allow you to scan via NFC, once you are on the correct screen above touch the center back of your phone directly over the center of the sensor, your phone should vibrate. If you have a bulky case and it is easily removable it is worth an attempt to try to scan without the case. Remember you only have to scan the sensor once to start it, then the sensor will communicate via bluetooth to provide readings real time.

Ensure that NFC is turned on your phone

Go to settings on your phone and then "Connections" and ensure the toggle is on for "NFC and contactless payments" 

If none of the above steps are resolving your issue, reach out to support@theiahealth.ai and we will gladly help you get the sensor to scan.