Can’ send or receive emails using iPhone 8 Plus
For outgoing mail I get “Cannot send email. The message was rejected by the server.”
For incoming emails I get “This message has not been downloaded from the server.”
iPhone 8 Plus, iOS 12
For outgoing mail I get “Cannot send email. The message was rejected by the server.”
For incoming emails I get “This message has not been downloaded from the server.”
Add an email account to your iPhone, iPad, or iPod ... - Apple Support
If you can't send or receive emails on your iPhone ... - Apple Support