Hi
Can you advise ->
Are you using the Stock email app.
What email client do you use and wether it's IMAP or pop3 you have set it up as.
Have you tried another email app from the App Store.
Have you tried deleting your email account in the mail settings and reset it up as a generic self help tip.
Are you on the latest iOS version.
Current Phone >
Samsung Galaxy s²⁴ Ultra 512gb.