Email not sending on iPhone

Same for me, for my case it seems that iCloud Mail is involved. I have custom email adresses (OVH hosted) and an iCloud email address. If I disable iCloud Mail I can send emails with my OVH email, otherwise I have the same alert as you, which is still showing no matter the settings saved (SSL, port number…).

All these email addresses work great on macOS though…

So any idea is welcome.

My wife has had some "sent" e-mails not sending since 16.1.1 was automatically installed. She has now gone into settings and there was a red notice to say that she needed to accept the terms and conditions. On accepting this the e-mails seem to be working and hopefully will continue to work.

Sporadically when forwarding/replying to an email we get "Cannot Send Mail An error occurred while delivering this message" We have turned off "Undo Send" and the problem still occurs. The problem started at IOS 15.7 and continues to 16.2

I opened a ticket with our HCL Email Vendor. They reviewed the logs of the devices with this error on the server.

This is HCL's response:

"IOS Mail app randomly providing a policy key 0

To be technically accurate, we are talking about the following policy key that flows in the http request header

X-MS-PolicyKey: 0

The 0 is unexpected and will force Traveler to return a 449 so that the client and server will negotiate a new policy key. Typically its going to have a value like the following:

X-MS-PolicyKey: 369126834

That value comes from Traveler in response to an Exchange ActiveSync "Provision" command.

Example response payload:

<Provision xmlns="Provision:">

<Status>1</Status>

<Policies>

<Policy>

<PolicyType>MS-EAS-Provisioning-WBXML</PolicyType>

<Status>1</Status>

<PolicyKey>369126834</PolicyKey>

</Policy>

</Policies>

</Provision>

So something is happening with the iOS Mail app such that it is losing the current policy key. Its not possible to see what is triggering this from the traveler server. Its possible that the client is seeing some error (network?) for which it then gives up and starts with a policy key 0. That is pure speculation and something Apple support will need to comment on. When communicating with apple, use the header term X-MS-PolicyKey. Hopefully they recognize what we are talking about."

I've worked with Apple Tier 2 support and they aren't aware of the issue. I don't know how to get the right help on this. I've tried to open a Developer Ticket.

::sigh:: DON’T SWIPE UP TO CLOSE THE EMAIL APP JUST AFTER SENDING. Advice that has been posted many times in this 8 page thread. iOS 16 has added a feature that lets you change your mind after hitting send; it holds the message for a period of time that you can set. If you force-quit the app before it sends the message is lost. If you don’t want this feature you can turn it off, but it is on by default.

In general, you should NEVER force quit any app unless it isn’t working; force-quitting slows down your phone and uses more energy than just letting it sit suspended, ready to restart. PLEASE read this→Do not close "background" apps | Communities.

FWIW, I have over 100 apps in the quick-launch app.

@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 had the same exact issue after an update. I was frustrated so I BCC'd myself on all emails. They weren't coming through. I didn't know about the "Undo Send Delay" feature that was added in the update. My habit was sending the email, hearing the "swoosh", then clicking the right button to lock my phone. Apparently if you lock your phone before the delayed send time expires, the email just disappears completely. It doesn't go to the drafts folder, outbox or anywhere. I turned this feature in Settings > Mail > Sending (at the bottom of the Mail menu. After that I've had no more issues. This is a terribly designed feature and should NOT be turned on automatically with the iOS update.

turning off send delay worked for me, or not closing app before delay period.

UPDATE - the above hint to turn off Mail delay worked for me

The problem is permanently solved 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.

Have you tried on both Wi-Fi and cellular data?

The next step is to reset network settings.

Thanks, turning off undo send delay worked for me.

Hi Metro287,

Thanks for using Apple Support Communities. It sounds like you've done a great job trying to resolve this issue on you own. The remaining steps in the following resource can help with sending emails: If you can’t send email on your iPhone, iPad, or iPod touch - Apple Support

If the issue persists, let us know if this also occurs when sending emails from your email provider's website. Be sure to include specific error messages and any other steps that you may have tried.

Have a nice day!

I did accept the terms and conditions right away - before trying to send email and realizing some was disappearing. I have disabled the “undo send” feature and that appears to fix the issue. But I’m still double checking that each email I send is actually sent….

I figured out the issue in my case. By default the undo send delay is 10 seconds. The mail will not be sent If I click the send and then close the mail app before the expiration time. I tested it and the mail behaves just like the way I described.

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)?