Nexus 5 requires repeated deletion of same incoming POP3 emails

[AC Question]

I have my own domain.

My domain provider forwards all emails received into my domain-email-address to my actual POP3 email address (that is, the one given to me by my ISP).

So I get all of these emails on my Nexus 5. I have the Incoming emails on the Nexus 5 as "delete from server when I delete (from device)".

But still after I delete the emails from both the N5 inbox and Recycling bin the N5 emails still regularly get downloaded again.

I heard this is a problem "repeated downloading of same messages" that occurs with POP3 emails.

Can I / how can I fix this please ?

 

[Golfdriver97]

I am not sure about this: Have you looked on the email site on a desktop?