Error in downloading mail on IMAP after ios 18 upgrade

VPN seems incompatible with 18.2

Seems to be an issue with the Mail app using IMAP in general. Happens with gmail giving a Network error (POSIX 54). Waiting for the update to hopefully fix this as email is not usable on the iPhone Mail app.

Thanks!

Yes, this has to be an iOS 18 issue. My MacBook Pro and Mac mini can access e-mail without a problem, but my iPhone 12 and partner's iPhone 16 (just purchased last week) aren't showing recent e-mails.

Maurice_HJ wrote:

I have exactly the same problem.

Tried to fix this, not sure but it might have to do with the certificates being self signed with dovecot.

I wondered about that. I do use self-signed certificates on my postfix server.

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.

I have a dovecot/postfix server as well and am using lets encrypt for ssl, and am experiencing this issue too. I do not think it's an issue with self signed certificates.

No VPN here either.

Curious, has anybody brought this up on any Dovecot mailing lists yet? Or somewhere else? I am looking at their recent archives and see nothing. I do see this mentioned on Mac Rumors forums.

I have dovecot 2.3.19.1 (9b53102964) on a stock Debian 12 system at the moment. Postfix is working fine.

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.

Thank you. This is very interesting. How would I find the separator that my Dovecot installation is using? I don't see the option in dovecot.conf.

plinss wrote:

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'

Thanks again. This morning I looked at my server configuration. (I installed Postfix/Dovecot using the Cutedge Systems GUI called MailServe. So Dovecot is installed at /usr/local/cutedge/dovecot.) The only configuration file appears to be . . . dovecot/etc/dovecot.conf. But that file doesn't contain a namespace setting, so I assume that Dovecot is falling back on whatever the default is.

Thanks for the information. I'm going to dig into it a bit more later on but for now, here's my namespace section. I've been using the same config for years and forgot how/why it was initially set up this way. It's always worked great in macOS Mail, Thunderbird, and Roundcube webmail.

The entire namespace inbox section in 10-mail.conf is actually commented out on my install.

# NOTE: Assumes "namespace inbox" has been defined in 10-mail.conf.
namespace inbox {
  # These mailboxes are widely used and could perhaps be created automatically:
  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }
  mailbox Junk {
    auto = subscribe
    special_use = \Junk
  }
  mailbox Trash {
    auto = subscribe
    special_use = \Trash
  }

  # For \Sent mailboxes there are two widely used names. We'll mark both of
  # them as \Sent. User typically deletes one of them if duplicates are created.
  mailbox Sent {
    auto = subscribe
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }

Alas:

Changing it from commented out to 'separator = "\\"' broke the server:

Nov 23 17:23:04 imap: Fatal: master: service(imap): child 91197 killed with signal 11 (core dumps disabled)

Changing it to 'separator = .' didn't break the server, but caused a new and questionable error message in iOS only:

Server code "CANNOT", server message "Invalid mailbox name: Name must not have '/' characters. 

Finally, Changing it to 'separator = \\' (no quotes) doesn't hurt (other mail clients work), but doesn't help iOS 18.x.

mangalapandi wrote:

…

May be i can help you to fix if you share the truncated logs while accessing Mail app to your server.

Well, I tuned on the several verbose debugging settings on dovecot, but it still doesn't seem terribly informative (personal info is obfuscated):

Nov 26 17:21:38 imap(pid 57854 user xxx.xxx): Info: ID sent: name=com.apple.email.maild, version=3826.200.121.2.3, os=iOS, os-version=18.1.1 (22B91), vendor=Apple Inc
Nov 26 17:22:11 auth: Info: od[sacl check](xxx.xxx,##.##.##.##,<KN3VR9gnEsAyZZIi>): mail SACL is enabled
Nov 26 17:22:11 auth: Info: od[sacl check](xxx.xxx,##.##.##.##,<KN3VR9gnEsAyZZIi>): user: xxx.xxx is member of mail SACL
Nov 26 17:22:12 imap-login: Info: Login: user=<xxx.xxx>, method=PLAIN, rip=##.##.##.##, lip=###.###.###.##, mpid=57854, TLS
Nov 26 17:22:12 auth: Info: od[sacl check](xxx.xxx,##.##.##.##,<L+zaR9gnFMAyZZIi>): mail SACL is enabled
Nov 26 17:22:12 auth: Info: od[sacl check](xxx.xxx,##.##.##.##,<L+zaR9gnFMAyZZIi>): user: xxx.xxx is member of mail SACL
Nov 26 17:22:12 imap-login: Info: Login: user=<xxx.xxx>, method=PLAIN, rip=##.##.##.##, lip=###.###.###.##, mpid=57854, TLS
Nov 26 17:22:12 auth: Info: od[sacl check](xxx.xxx,##.##.##.##,<bvHaR9gnE8AyZZIi>): mail SACL is enabled
Nov 26 17:22:12 auth: Info: od[sacl check](xxx.xxx,##.##.##.##,<bvHaR9gnE8AyZZIi>): user: xxx.xxx is member of mail SACL
Nov 26 17:22:12 imap-login: Info: Login: user=<xxx.xxx>, method=PLAIN, rip=##.##.##.##, lip=###.###.###.##, mpid=57854, TLS
Nov 26 17:22:14 imap(pid 57854 user xxx.xxx): Info: Connection closed (UID FETCH finished 0.684 secs ago) in=474 out=417293
Nov 26 17:22:14 imap(pid 57854 user xxx.xxx): Info: Connection closed (UID SEARCH finished 0.765 secs ago) in=2379 out=614477
Nov 26 17:22:14 imap(pid 57854 user xxx.xxx): Info: Connection closed (IDLE running for 0.001 + waiting input for 1.194 secs, 0.001 in locks, 2 B in + 10 B out, state=wait-input) in=85 out=1332

All I can say is that the app continues to say "checking for mail" long after the server says Connection closed, and other connections don't have Connection closed messages at all.

any update from apple support? i know there are a few mixed issues in here, but I also see the same issue with an iOS 18 client and our dovecot server. Our separator is default (period) so not the double-backslash. I had submitted a Feedback Assistant ticket with logs etc November 6th and still have not gotten any resolution or natable update from Apple other than providing further information. Perhaps I could reference a similar Apple ticket from those of you who have submitted them. My ticket is FB15701211 fyi.

running a dovecot imap server... I can see the folder structure for mailbox subfolders is using "." as the separator. In the conf.d/10-mail.conf I see

namespace inbox {

  # Namespace type: private, shared or public

  #type = private

  # Hierarchy separator to use. You should use the same separator for all

  # namespaces or some clients get confused. '/' is usually a good one.

  # The default however depends on the underlying mail storage format.

  #separator =

  # Prefix required to access this namespace. This needs to be different for

  # all namespaces. For example "Public/".

  #prefix =

  # Physical location of the mailbox. This is in same format as

  # mail_location, which is also the default for it.

  #location =

  # There can be only one INBOX, and this setting defines which namespace

  # has it.

  inbox = yes

  # If namespace is hidden, it's not advertised to clients via NAMESPACE

  # extension. You'll most likely also want to set list=no. This is mostly

  # useful when converting from another server with different namespaces which

  # you want to deprecate but still keep working. For example you can create

  # hidden namespaces with prefixes "~/mail/", "~%u/mail/" and "mail/".

  #hidden = no

  # Show the mailboxes under this namespace with LIST command. This makes the

  # namespace visible for clients that don't support NAMESPACE extension.

  # "children" value lists child mailboxes, but hides the namespace prefix.

  #list = yes

  # Namespace handles its own subscriptions. If set to "no", the parent

  # namespace handles them (empty prefix should always have this as "yes")

  #subscriptions = yes

}

# 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

}

This location does align with file system

/Library/Server/Mail/Data/mail/users/%%u

still get POSIX 96 on occasion..., no vpn ever used. Some people say POSIX 96 error goes away with a reboot. Who cares if the error goes away but the email doesn't sync or land in the Inbox...?

iOS 18.2 installed overnight and it is already showing serious bugs ....but no Mail IMAP fix. I see the number of Unread Messages seems to be more accurate but when I visit that Inbox for IMAP, the messages are not there. Going to macOS Mail on macOS 15.1.1, I find the messages awaiting...it all went to crap in iOS 18...