As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SATCOM CALLS UNSUCCESSFUL- CALLS DIAL AND ARE ANSWERED BUT NOTHING IS HEARD ON THE AIRCRAFT END ON SAT 1 OR SAT 2. GROUNDED - YES. T/S SATCOM SYSTEM B737-800 AMM 23-15-00/601 AND 23-27-00-730, B737-800 FIM 23-15 TASK 801. NO HISTORY 30 DAYS. OK FOR SERVICE.