Please verify all of the following:
No – or improper SIM inserted (for all Spirent testing, please use Spirent SIM card. For at&t related testing, please use UICC 64k card programmed with appropriate PCOM script)
UE does not support - or is not enabled for the tested band
RF cable is not – or improperly connected or damaged
UE is set to support to UMTS only or GSM only