Hi @Wychfinder,
Could you share a screenshot of your flow?
You said that a notification email would be sent to a specific people, how do you specify this person?
If you are using a dynamic content, please make sure the dynamic content does return a valid email address.
Besides, please suggest email receivers who cannot receive the email check their junk email box, I am wondering if their email settings will consider emails from Microsoft Flow as spam.
Best regards,
Mabel