There are various reasons Reasons For Not Receiving Email in outlook:-
1. Not allowing enough time.
2. Sender doesn’t have the correct email address.
3. Outlook setting.
4. Misspelling of email addresses is a very common reason for emails not being sent.
5.Email was saved as a draft by mistake.
Read more here:- https://www.datarecovo.com/outlook-not-receiving-email-how-to-fix/