Customer emails not showing up on Mac or iPhone

vandy36 wrote:

I have one customer who's email I am not receiving on my Mac or iPhone.

Are you using Outlook? Try checking the Junk folder. If the messages are going there, you might want to try setting up a rule to make sure they go to your Inbox - Set up an inbox rule in Outlook for Mac - Microsoft Support

If they aren't in Junk, it's likely an issue on their end. Do they have your email correct? Can they send email to others successfully? Are you sure they're sending emails?