Issues with open E-Mail APP

So your issue is NOT solved. I would try to install a fresh copy of you iOS.

To do that, create a full backup of your iPhone, then restore ir to factory settings and, in the end, set it up as new, following the steps provided in this support guide:--> Restore your iPhone, iPad, or iPod to factory settings - Apple Support

When done, restore your data from your previously made backup:--> Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Please let me know how it goes.

Regards

Giulio

Check your e-mail account settings, or, if you get no help, delete that account, restart your iphone, then add your e-mail account again.

Regards

Giulio