Hello and welcome to Apple Support Communities rusty_kit_kat,
I see that you're having an issue with the mail account on your iPhone. I know it's important to have this app working properly, and I'd be happy to help.
If you're using the Mail app on your iPhone, force close the app, restart your iPhone and test to see if the issue remains.
How to force an app to close on your iPhone, iPad, or iPod touch
Restart your iPhone
If the issue persists after trying the steps above, remove the mail account from your device, add it back and then test again. The article below will guide you through those steps, under the section titled "Remove your email account and set it up again".
If you can’t send email on your iPhone, iPad, or iPod touch
Hope this helps.
Have a great day!