If 'No Service' displays in the status bar of your iPhone 7, view this info.
Apple has determined some iPhone 7 models may show 'No Service' in the status bar even when cellular coverage is available. Verizon is a participating carrier in this program supporting Certified Like New Warranty Replacements (CLNR) for manufacturer in warranty and all Verizon Extended Warranty customers. If you have an out of warranty iPhone 7 without Extended Warranty, either standalone or through Total Mobile Protection (TMP) or Total Equipment Coverage (TEC) that indicates 'No Service' and becomes unrecoverable, contact Apple for assistance. To view affected model numbers, including additional details from Apple, refer to this iPhone 7 Repair Program support page.