Email Push Stopped Suddenly

Have an Iphone 6S plus with Verizon running IOS 11.1.1. Have used mail app and Icloud mail for years with push working flawlessly. For some reason, seemingly unrelated to any software update or app download, the push feature stopped working last week. I have triple checked the push setting, restored phone with a prior backup, signed out of Icloud, etc., and still no push functionality. Only get email with manual check. Email push to macbooks is normal. No change with wifi vs. LTE.

Any help appreciated.