Email: Connection Doctor

I continuously get a 'connection' issue with my email when added on the native email app. I open the 'connection doctor' and there is no issue and the email will send but it will show that it is struggling to send.

Is there anyway to set up email correctly and limit the chances of this connection issue. Any emails I delete are not replicated on the host email server (i.e. gmail/hotmail/live).

My attempt at solutions so far as has been:

• remove internet account via settings and re add the internet account.
• to 'sign out of all areas' on the host email server and then log back in.