Email

Have you tried deleting the account, restarting the device, and then adding the account back?

Mail – Setup on a device    

Mail - If you can’t send email on your iPhone, iPad, or iPod touch

Mail - If you can't receive email on your iPhone, iPad, or iPod touch     

Hi,

If you use iCloud email, make sure you got enough iCloud storage to receive emails.

If you got enough iCloud storage, check your spam box.

If you use another email client (Gmail, outlook…etc), also check your spam box, and if you set up your mailbox in the Mail app, make sure your email account doesn’t need any action, like re-enter the password..etc (settings/mail/accounts)