I am on charter.net and can no longer send emails from my iphone 8. Settings have not changed and are correct.

Yeah, but when you are on Wi-Fi, your iPhone is using Wi-Fi and not mobile data to send emails, messages, check for notifications, downloads, etc.

Head to Settings > Passwords & Accounts > your email account > account name:

• tap on SMTP (under the 'Outgoing Mail Server' heading)
• tap on your Primary Server and enter your username password, even of It says that it is optional, enter the information anyway.

You can try quitting mail completely, turn Mail off in that account, restart your iPhone and turn mail on again and then see if it will send emails.

Using Thunderbird on your computer should not cause a problem.

Delete the account from your phone and add it back. That will download entirely fresh settings. Note that just turning off the account will not achieve the same thing.

Why are you afraid? You delete the Charter email account. You add it back by putting in your email address and passcode. If you're having a problem doing it over WiFi, do it over a cellular connection. It should take all of about two minutes.

Interesting - when I turned off wifi, I was able to send mail from my iphone. ????

Is that before or after you deleted the account and re-added it?

Try turning your router off, waiting 5 minutes then turning back on.

Does iPhone give you any error?

Did you try to send an email using Wi-Fi? What are the results?

Does an issue persist when you are using mobile data?