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.
Reboot after update
Reboot your iOS device and check if the issue is still there
Same issue, on iPhone and iPad, started with upgrade to iOS 18, not fixed with 18.0.1.
I can access the same accounts fine from a desktop MacOS Mail app.
Dovecot (v2.3.20) debug logs show a successful TLS connection and authentication, opening the INBOX, executing LIST, then immediately disconnecting. No errors reported on the server side.
I also run a slightly older version of Dovecot (v2.3.17) on another server and my iOS devices can get mail just fine. I'm wondering if the iOS 18 clients are doing something slightly non-standard causing newer Dovecot versions to close the connection.
mangalapandi wrote:
This may not be the Mail App issue, When i got new iPhone with iOS18, i got the same issue after the migration and even i deleted the account and recreated in Mail app, it did not worked. Then i have checked my server about the dovecot error log and i noticed that its had issue in keeping the authentication session and i fixed it, then Mail app started getting message and its not showed any error related to POSIX 96 till now.
This is very significant, and probably the most useful post I have seen respecting this problem! But, how did you fix it?!?
This means, ironically, apples own (discontinued) server software also won't work with iOS 18 because it runs dovecot.
The case finally landed in Cupertino! We have a case no. and the developer are in the process of analyzing the problem and implementing a solution. It is a bug that will be fixed in one of the next releases. As soon as I have news I will post them...
plinss wrote:
…
Those here running their own server, I'd like to hear what your folder separator is set to. If you change it to anything else, I expect your connection problems will go away.
…
# shared namespace configuration
namespace acl-mailboxes {
type = shared
separator = .
prefix = shared.%%u.
#location = maildir:%%h/Maildir:INDEX=~/Maildir/shared/%%u
#location = maildir:/Library/Server/Mail/Data/mail/%%u:INDEX=/Library/Server/Mail/Data/mail/%%u/shared
location = maildir:/Library/Server/Mail/Data/mail/users/%%u:INDEX=/Library/Server/Mail/Data/mail/shared/%%u
subscriptions = no
list = children
}
I too have fallen foul to the error POSIX 50 where my mailboxes won’t update.
However, I found a way to temporarily fix the issue merely by coming of my WiFi connection and using my data plan to open my mail. It works well enough for me.
I’m sure that the Apple tech team will come up with a permanent fix soon though.
@ferrerod I have no idea how they did that, I am sorry. But I have found on their forums, that the necessary fix to be applied is this: https://github.com/stalwartlabs/mail-server/issues/765#issuecomment-2362931057
Hope that helps somebody.
Hi, i see a similar problem, and solved changing the login greeting of the imap server to not contain non-ascii characters (in my case Dovecot server).
This affects me too, on both iOS and iPadOS 18.1, using my own domain. I can usually get it working again temporarily by force quitting the Mail app and restarting it.
I heard that if you reboot the device after updating it and logged into your email account that you wouldn't get the error.
Already tried the following;
I finally just moved to the outlook app. Everything is working fine with that. Seems like the issue is with the mail app itself and not IOS 18.
If you had of mentioned it was a Outlook account the two suggestions I make, is 1. You reenter it using the Exchange option and if that doesn't work, then I usually suggest you download the Outlook app on the App Store.
Contact Apple Support
Contact - Official Apple Support (CA)
If you ever get them on the phone explain it to the rep, but don't let them put you off. Have it expedited and keep it going until then can either fix while you are on the phone or give you a timeline on when it is going to get fixed.
“Those here running their own server, I'd like to hear what your folder separator is set to. If you change it to anything else, I expect your connection problems will go away.”
I am running a dovecot server, and I will have to figure out how to check the configuration for this information. However, I believe the separator is a dot, because I can’t create an imap folder name with a dot in it (I.e. purchases.home becomes purchases with a sub folder named home)
Error in downloading mail on IMAP after ios 18 upgrade
