Error in downloading mail on IMAP after ios 18 upgrade

I have the same problem, but it occurred way before I downloaded IOS 18:

I have Hotmail as my main email account—have for decades. Lately, the mail app on my iPhone Willy Nilly decides my password is incorrect and stops receiving and sending mail. I use the same password I have been using since I changed it earlier this year and sometimes it gets my mail working and sometimes it doesn’t. Oddly enough, the mail app on my iPad doesn’t behave this way, logging on to Outlook via a browser to access my mail doesn’t have a problem—it’s just on my phone mail app. I’m at a loss as to how to fix this. Any help would be greatly appreciated. 

I’m getting: Network Error POSIX 96 

I am unable to download my mail using the native mail app after upgrading to IOS 18. I am getting the following error; “Unable to create a secure connection to the server ("bad certificate format -9.808).”

The mail configuration is on imap with SSL and TLS.

Thank you for persevering with the case!

However, I find it strange that Apple is now looking at your iPhone individually in detail.

Has Apple still not realised that thousands of users worldwide have been experiencing these Apple Mail problems since the update to iOS 18? This is not an individual problem of a single iPhone! My German mail provider has also confirmed to me that it must be an Apple error. He rules out the possibility of a fault with himself or the phone provider. Best regards from Berlin!

My iPhone was updated to 18.1 and I noticed immediately that my imap email account would not refresh for hours, despite sometimes advising all Mail had been downloaded. Whenever I checked the same account on my iPad or M2 MacBook the mail came down immediately. After the 18.2 update I thought issue might be fixed but after several days it is the same. Only iPhone is affected. The error message seen for the first time today is POSIX 96 - imap settings might be incorrect. All settings are the same on the iPad and MacBook and are correct on the iPhone. Conclusion - the update to 18.xx has caused the issues. I’ll try Spark instead of Apple Mail as I have been told that other Mail clients are not affected with this very inconvenient bug.

My fix was to go to IMAP server name a type over the greyed out forward slash following the server name.

I backed out of settings and shut down the iPhone, and then restarted it a minute later. After the phone rebooted I went to mail and pulled down the mail to refresh it from the server. After a few seconds (which I think was the IMAP server resyncing with my mailbox, all my mail for the last few days came down. After two days it is behaving as it should with new mail appearing when it should. I note that this problem was not evident in my iPad which is iOS 17.x and not on my M2 MacBook Pro, nor on my partner’s iPad with iOS 18.1. I can only conclude that Apple can solve the mystery of this and the other issues with email that can’t be solved with this fix.

riyeau wrote:

I was having the same issue all day on the Mail iOS app with both of my Gmail accounts. I then realized I was connected to a VPN on my phone so I disconnected it and it immediately fixed the email issues!

Glad you got the problem fixed. I don't use VPN on my own phone, so there must be another issue.

“Same Problem for me - Support said the problem is known and seems to occur if you use your own domains”

Did they suggest a workaround pending a fix? This is a serious problem.

My iPhones started downloading e-mail once I logged off Norton's VPN

https://doc.dovecot.org/2.3/configuration_manual/namespace/

In my case (Debian), it's in /etc/dovecot/conf.d/10-mail.conf, look for 'namespace inbox'

@mangalapandi

That is an interesting hint. What exactly did you do? Customization in dovecot.conf? And if so, what exactly?

I may be able to solve the problem for myself too. I found dovecot.conf in my mail configuration...

Thank you for any further information !)

In my case, I still had the old Hotmail account on the Mail app as my primary email. I got in a live chat with Apple help and they had me delete the Hotmail account and just install Outlook as my primary email. That fixed it; I can now receive/send email using my original hotmail address through outlook. I hope this helps someone—sorry I’m not more tech savvy.

I experienced this error today, but even with a higher debug level on my dovecot server, I did not see any server side errors. No recent changes other than iOS 18.1.

Hopefully an upcoming updated fixes it. It happens at random times.

Obi1net: Thanks for the info. Can you clarify the procedure you used? In Mail settings/Advanced I see a greyed-out slash for "IMAP Path Prefix". Is that the one you mean? And what do you mean by typing over it?