Have you had an annoying problem on your iPhone or iPad where you can receive emails, but it won’t send? I’ve had this problem for a few days now when things used to work without issue. The problem seemed to have popped up after one of the latest updates to iOS 9. The only way I could get my email to work was delete my account and recreate it. I finally found an obscure post from the old days of iOS 8 that has fixed my issue. I’ve updated and posted the steps below, hopefully they’ll help cure your problem too.
1) Go into Settings > Mail, Contacts, Calendars > then select the email account your having problems with under the ACCOUNTS section
2) Continue thru on the Account from the IMAP page
3) Select SMTP in the OUTGOING MAIL SERVER section near the bottom of the IMAP Account Information page
4) Press on the mail address in the PRIMARY SERVER section
5) There will be another password listed in the OUTGOING MAIL SERVER section here. Re-type in your password with the correct one.
6) Click Done to get all the way out of settings.
Now when you access your email account, you should be able to both receive and send. Don’t ask me why the outgoing mail server password gets corrupted – I don’t know. But apparently it does.