emails disappear without sending

Same issue here. Reproducible on my iPhone6 running 10.3.1

-- Compose new email on Gmail in a browser

-- Email appears in Drafts folder on iPhone, send it via iPhone

-- Email is not delivered, not in Sent Folder

Tried it with a friend's iPhone, there is no issue on his iPhone 5

Are you saving drafts and send messages local in your iPhone or at mail server?

Check Settings>Mail, Contacts, Calendars>your account>mail>advanced>mailbox behavior.

Is IMAP account or POP?

Try this for Gmail accounts.

Settings>Mail, Contacts, Calendars>your.Gmail.account>Account>advanced>mailbox behavior. Tap on Drafts Mailbox and select "Drafts" in "On My iPhone" area.

I read the sugestions here and am very sad Apple has not properly given a solution to this issue.

After critical emails dissapeared I WAS SO MAD.So I tried a few of these other suggestions and noticed my email push was changed by the last update,I had it set to manual before the update but found it set back to push. This is the olny thing that worked for me [so far 15 emails sent yes really sent not just gone]

-settings

-mail,contacts,calendars

-fetch new data[which now said 'on' [not manual where I set it]

-turned push off and set 'every 15 minutes'

Yes it is a pain in the Samsung but now nothing is just gone it sends ,you might try the 'manually' which searches each time you open a mail account and check it often.

I tried turning it off [push home and top button at the same time] and hold until screen went black, then a reset in iTunes but none of that worked. This must be Apples way of getting you to buy a new iPhone 5 I sure dont see that phone having this problem [I miss Steve Jobs he would never let them just ignore it]

I am using a iPhone 4 [no S] with Yahoo and Gmail through AT&T in Alaska which has very limited 4g coverage mostly using a 3g coverage from them.

Sure hope this helps you

Wow, the exact same thing has been happening to me, but only for the past 3 or 4 weeks.

I'm a university teacher and I often write my students quick replies with my iphone. Recenlty, though, several of them have claimed they never received my emails. At first I didn't believe them. But then upon closer inspection, I searched my outbox and found that the emails were simply gone. I began to test whether I was going crazy or whether the iphone was really just deleting my messages. I no BCC myself on most messages, just as a test, and sure enough about 10-15% of my emails are never received and disappear ENTIRELY from both the phone and the email server (Yahoo). They don't get stored in DRAFTS, or OUTBOX, they simply vanish.

I'd love to know if there's a fix for this that will work. I'm on a 4s, running IOS 5.1. Again, I don't think this problem ever occured until recently. I love my phone and use the mail app dozens of times a day for work and personal reasons, but I'm getting nervous that it's not a reliable way to email people!

Did you tried to send and receive mails of your Yahoo account from web browser? Are everything ok there?

Yes, I've done that as a test. It worked fine. But it's clunky and hard to read. The problem was (I believe) with the Apple mail app, not yahoo. I've never had a mail disappear like that except on the iphone.

Did you setup your Yahoo account by selecting "Yahoo" setup when you add the account in your iPhone? If yes try to setup by selecting "other". Google for instructions hoe to do this.

So you're saying I should delete the account, and then relaunch the mail app, and instead of choosing Yahoo, find an alternate way of setting up the mail to be yahoo? I'm a bit confused.