Mail fail
My email failed to be loaded, how can I fix this?
iPhone 6 Plus, iOS 12
Question marked as
If mailbox is full the emails will not upload check iCloud storage Check your iCloud storage online or on any device - Apple Support
Send and receive iCloud Mail on all your devices and keep Mail settings up to date - Apple Support
Or else if mail received has large attachments see this article Add an email attachment in Mail on iCloud.com - Apple Support
Read If you can't receive email on your iPhone, iPad, or iPod touch - Apple Support