emails not auto refreshing and appearing twice

emails not auto refreshing and appearing twice

Hi

This problem is not just happening to me, it also occurs for some of my clients.
Whenever an email is received, it does not appear in the inbox unless the page is refreshed. Also, after deleting a new email, shortly after I get an alert in the bottom right of my laptop that an email has been received, I then have to go back to inbox and delete it for the second time.

Can you please advise.

Kind Regards