Please check the following: 

A) Logged in 

B) You have a valid virtual card for the site you are at and that it is not expired. 

C) Check with the site admin, that you are allowed through the door / gate at this time. Your entry may be restricted by the physical access control system. 

D) Check bluetooth is on, at the phone level (i.e. on for all devices) 
E) Check bluetooth is on at the settings, app level as follows