Even after a successful repair, the device will likely show "No Service" because the new IMEI is not yet "certified" by the firmware.
Go to the "Backup" tab and click Read EFS . This is a critical safety step to prevent permanent baseband loss.
Go to Settings > About Phone > Software Information and tap "Build Number" seven times.
Repairing the IMEI on a Samsung Galaxy S7 (SM-G930F) Go to product viewer dialog for this item.