Not receiving emails? Check these 6 things

Check these in order

1. Spam or Junk folder. If you find it there, mark it Not spam so future emails arrive properly.
2. Other tabs and folders. Gmail's Promotions and Updates tabs, and Outlook's Other inbox, hide mail in plain sight.
3. Is your mailbox full? A full mailbox bounces new mail. See Mailbox full?
4. Rules and filters. A rule may be moving or deleting mail. Gmail: Settings → See all settings → Filters and Blocked Addresses. Outlook: Settings → Mail → Rules.
5. Blocked senders. Make sure you haven't blocked the sender by accident.
6. Forwarding. If your email forwards to another address, the message may have gone there.

Ask the sender

Ask them to look for a "delivery failed" bounce message. It says exactly why it didn't arrive. Also double-check they have your address right.

Using your own domain?

If nobody can reach you, your domain's email settings (MX records) or hosting may have a problem. That needs a quick look from whoever manages your domain.