I am unable to download my mail using the native mail app after upgrading to IOS 18. I am getting the following error; “Network Error (POSIX 96)”
The mail configuration is on imap with SSL.
iPad Pro, iPadOS 18
@ferrerod:
Here's the main part of the response I got from Fastmail who diagnosed and solved the problem on my account. It seems there was a bug in their mail engine that was benign until the iOS18 update, then no more. I hope this helps.
We had a bug which put random data into the HIGHESTMODSEQ value for some users. Their account was affected by this. We didn't think it was an issue because there was still heaps of number-space left, but the HIGHESTMODSEQ values were higher than a signed int64 can hold. This was fine because we use an unsigned int64_t internally, but the spec was updated a few years ago to make it a signed value, so we were strictly wrong.
Apple's parser couldn't handle these oversize numbers, and failed.
--
This has now been fixed by resetting the HIGHESTMODSEQ value for these users which also means this will never happen for them again.
ferrerod wrote:
Did fastmail tell you what technically they did? No one else has a workable solution. Some of us support our own mail serves - though perhaps rare.... would be great if you could get them to tell you exactly what they did for IMAP solution.
Stephen, how's your testing of removing the advertising of the IMAP IDLE feature going?
I have noted that adjusting my Pihole filtering to stop blocking iCloud Private Relay servers helped substantially - but not completely. Re-enabling the blocking of the servers brings back all the problems. During testing of this I noted that there is likely some interplay with DNS TTL values, which can temporarily make it look like things are fixed when in reality they are not.
I have an open case about this with Apple support; I spoke to my contact person again today and he confirmed that the engineers are aware of the problem and are actively investigating. I've signposted him (again) to this thread. He was keen to point out that they are keen to hear of any fixes, workarounds, etc in support of trying to find ways to reproduce the problem etc. I specifically noted to him the observations made about IDLE and he said he would pass this on.
Fingers remaining crossed for a fix soon.
[Edited by Moderator]
I really think that Apple has choosen to deny this bug , because how to explain otherwise that after recent upgrades serie 18…this bug remains unfixed ??? What to do ??? I am not an IT , so I am not able to found out by myself a fixing solution !
Just installed IOS 18.2 on my iPad Mini and.... still in error!!! (POSIX 96). Nice... this is getting ridiculous for a basic function as email app to get a regression of this size.
I will give this a try in a few...meanwhile, I can see activity on dovecot email lists also being hit by this iOS 18 mail bug. I will try to cross post about stalwart labs findings on dovecot in hopes that it may help them....meanwhile, we hope the reference to the EU complains will motivate Apple to actually provide a solution such as how they deal with IDLE being sent. Breaking mail for working clients so that Apple Mail works in iOS 18 is a compromise we should not need to make.
[Edited by Moderator]
Error downloading mail
Clyde - 2.2.30.2 (c0c463e)
Yeah and apple doesn't like it when you call them out and say that Microsoft Outlook works on the iPhone better than their native mail program. Truth is Apple has been aware of this issues for years, but most recently post ios18 💩. Sad... instead of fixing it they hide upset customers posts.
Are you sure you have it working? It worked initially worked and got inbox email and the folders, but then went back to failing.
Apple acts with lightening speed to take down any post that calls them out. But if they would put the same effort into helping solve this issue for its customers then they wouldn't need to police things. Sad that a Microsoft outlook product works better on a Mac than the native mail software. I run multiple businesses and this is completely unacceptable.
Go ahead Apple. Show us how thin your skin is again.. Just fix it. You know all about it.
I have also tried remove all certs (including a CA) and reinstalling but nothing has worked. Not really sure what your WIFI would have to do with the issue.
I just migrated an iOS 18.2 iPhone to my self hosted postfix/dovecot setup and it was having problems getting mail with IMAP. It would say "downloading" and do nothing. It would not sync folders. I tried changing dovecot namespace separators, capability strings, etc. Nothing helped. I disabled pihole on my LAN - no change. If I moved the phone to the mobile connection it worked correctly. I removed all SSIDs on the local wifi network and re-signed in to one of them. Since reconnecting to wifi, mai lis working correctly. I have no idea why, but that is what it is doing.
Well I had no luck with going back to 17. Apple absolutely doesn't let you go back. I even tried from a backed up .ipsw file (how frustrating).
Yes, I tried this exact string, `dovecat reload`, then `netcat <ip> 143` and confirmed the string was right.
What version of dovecot are you on?
I was able to resolve the issue POSIX 96 by logging into Passwords and adding a new Password Profile using the same username and password. The one saved for the BT email seemed to conflict when using the original Password Profile in the Advanced Settings for the Mail
App. Once a new profile was set up I changed the autofill password and it resolved the issue and started to download the emails.
good luck with that - iOS 17 isnt signed anymore. your syntax is 100%? the line in my config is:
imap_capability = IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE XAPPLEPUSHSERVICE AUTH=CRAM-MD5 AUTH=PLAIN AUTH=LOGIN
you can also check what yours looks like by running `doveconf -a | grep imap_capability`
Yes I read that and taking the original string I used with netcat (rather than telnet) without IDLE was one of those strings I tried and failed. I'm trying to revert to iOS 17...wish me luck.
Error in downloading mail on IMAP after ios 18 upgrade
