Email not sending on iPhone

I’ve done extensive testing, with several different email accounts. I hit Send, then immediately lock my phone. Locking my phone does not prevent mail from sending, even if locked before the send delay times out.

However, if I force-quit the mail app before locking the phone, or also not locking the phone, force-quitting the mail app DOES prevent mail from sending, every time. Whether I lock the phone or not.

@Lawrence, this thread is for folks who have the problem, not for those who don’t.

The permanent solution to the problem by simply going to Settings … Mail … and switching off “Delay Sending”. It will then send the email immediately, regardless of locking or quitting etc. etc.

No further testing is required.

I was replying to a post that said that locking the screen prevented mail from sending. So I tested that extensively, and found that locking the screen DOES NOT prevent mail from sending.

I would think that was useful information, but you don’t have to use that information if you don’t want to.

Yes, switching off a very useful feature does solve the problem, but is only required if you insist on force quitting mail. If you don’t force quit mail you will have no sending problem.

Just found this thread: I've had the same problem with one of my email system in iPhone's 'Mail' ever since I upgraded to iOS 16.5.1, which simply sends my emails to 'Outbox' and it stays there; I have 'Delay Sending' switched off. I have iOS 16.5.1 on my iPad and the same email system in 'Mail' sends no problem at all, with exactly the same credentials: most odd and REALLY infuriating!

Hi, many thanks for your timely reply which I appreciate. I have tried all the fixes mentioned above: the credentials (Outgoing Mail Server - Passwords etc.), are the same in iPad and iPhone - iPad functions perfectly, iPhone doesn’t: iPhone emails stay in in ‘Outbox’ in this particular email system that I mention. With any email I send in this particular system I get: ‘Cannot Send Mail’ The server rejected the recipient’s addresses. The message has been placed in your Outbox.

Incidentally, I believe that my issue has everything to do with this thread, 'Some Mail not sending in iOS 16’ no?

Anyway, thanks for your attention to this.

It is not the same problem: The problems in this thread specifically say that the message is not saved in the Outbox or Drafts. Yours is saved in the Outbox, it just isn’t sending.

Do you have VPN installed on your phone? If so, try deleting the VPN profile and app.

Ah, OK you're right: I was taken in by the header which seemed to fit my circumstances?

I do in fact have a VPN on my iPhone though it’s switched off; I’ll try deleting the VPN profile and App anyway and see what happens: thanks again.

Hmmm……….deleted my VPN profile and App, shut down and re-started my iPhone and the fault remains the same: a most curious fault?

I have a few system operating in ‘Mail’ working fine: I've removed and reinstalled this particular email system from ‘Mail’ several times since the fault started a few days ago; unfortunately I can't seem to find a way around it?

Again, thanks for your help.

Hi Lawrence, tried on both Wi-Fi and cellular data, reset network settings, nothing worked, then I simply put my user name and password in at the “outgoing” settings (even though it said they were optional) and ..... it works like a charm! Thanks for your help, and apologies to have taken up your time with this but sometimes we just can't see what's staring us in the face can we (least not me, anyways, duh)?

It’s always bothered me that outgoing settings are labeled “optional”. They aren’t, except in the very rare instance of the email address domain being the same as the network domain. e.g., your address is me@example.com and your mail network provider is example.com. For all practical purposes this is never true in the modern world.

I now have 16.2 with “Outgoing server issues on both my iphone 11 and my ipad air “ I am being advised to check my SMTP which I cannot find of course.The other advice from Apple Support is to delete my Mail Account

That means the password or other settings for outgoing (SMTP) mail server are missing or wrong. This can happen if you change your mail password but don’t change it in 2 places, for both incoming and outgoing. There’s an easy way and a hard way to fix an SMTP issue. The easy way is to go to settings/Mail/Accounts, tap on the account and delete it. Then restart your phone. Then go to settings/Mail/Accounts again and add it back.

The hard way is to go to settings/Mail/Accounts, tap on the account, tap on account again, tap on SMTP, tap on primary server, then enter all the correct settings. The hard way will not work for iCloud or Microsoft email accounts, for those only the easy way will work.

It is not a bug. It is a misconfiguration of your account setup. It will never be fixed by Apple, because the problem has nothing to do with Apple. If it is an IMAP account you won’t lose anything by deleting and reinstalling it. But lets narrow it down further. Who is the email provider (Apple, Google, AOL, Yahoo, Verizon, AT&T, Spectrum, Optimum, Cablevision, btinternet, etc)?

Neither. It is 100% a mail provider problem. I have 7 email accounts, all from different providers, on my iPhone, my iPad and my MacBook Pro. My wife has 2 accounts on her iMac, her iPhone and her iPad. All 9 work perfectly all the time. You can believe whatever you want, but that won’t solve the problem until you consult your ISP’s tech support, or take my advice.

Similar issue. However it "sends", I hear the swoosh. it disappears, But then it is not in the sent folder, not in the drafts, not in the outbox, no where, and I follow up with intended recipients, they didn't get the email. this seems to happen more with forwarded and replied emails than new created but happens with all. this is a HUGE issue especially when work time related emails... claiming "but I sent the email!!!"