When using the social distance alert app ensure that bluetooth is enabled and the necessary permission have been granted.
If you are unable to detect any nearby devices go to the settings page and increase the scan range to max. Then slowly reduce the scan range until the desired sensitivity is met, alternatively you can use the calibration option also on the settings page.
If there are no nearby bluetooth enabled devices powered on then the app will not find anything.
If you have any questions or suggestions about the app, do not hesitate to contact me at firstname.lastname@example.org.