The AT&T or T-Mobile SIM is most likely not activated
AT&T & T-Mobile will not make test calls unless an active sim is inserted. It doesn't mean the test call is defective; it is simply the by-product of GSM device abilities.
When the sim reader is bad the message displayed on the top left of the device screen will be "No Sim"
When it is incompatible it will say either "No Service" or "Invalid Sim"