Error in downloading mail on IMAP after ios 18 upgrade

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.

I probably should NOT have purchased a new iPad… everything was working fine on the previous iPad, and still work fine on my iPhone, iMac and MacBookPro…

Apple, please debug before selling? Quality is steadily decreasing with time…

It's fixed! It magically started working again on both my iPhone and iPad yesterday. They must have fixed something on the back end, because I didn't do an iOS update this week and didn't change any settings.

I have the same problem with my email, French internet access supplier, Free. It’s impossible to send email: Network error: (posik 96) It’s only with IPhone on IOS 18, not before, and not with my IPad or Mac. Apple Store wasn’t able to fix the problem. And it’s impossible to change for IOS 17. Then I can’t send email with my iPhone. When Apple will fix this bug??

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?

Hi George. My apologies for not being clear.

Yes that greyed out slash was the one I meant. By typing over it I meant that I typed a slash to replace the one that was greyed out so that it was black as other text appears when you use the keyboard. It fixed my problem after I did this and rebooted. The exact solution was needed a few days later but so far the fix stuck this time. Sadly I think this is just one symptom of other issues.

Obi1net wrote:

Hi George. My apologies for not being clear.

Yes that greyed out slash was the one I meant. By typing over it I meant that I typed a slash to replace the one that was greyed out so that it was black as other text appears when you use the keyboard. It fixed my problem after I did this and rebooted. The exact solution was needed a few days later but so far the fix stuck this time. Sadly I think this is just one symptom of other issues.

Thanks very much for the crystal clear reply.

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.

Sending emails is possible in iOS18, only receiving en viewing the imap mail content is not possible in iOS18 in combination with dovecot.

I hope they fix this because this is one of the most essential functions of the device.

Thanks. This is good information. Yours is a much newer version of Dovecot than mine. Considering that and the fact that you are using certificates signed by a recognized authority further narrows the possibilities.

When my last post was upvoted I received an email saying that this thread has been viewed 24988 times. Clearly this is a widespread problem.

I'm not using any other server or VPN, just the mail app provided by Apple and the standard configuration on the iPhone, upgraded to 18.1.1 and the problem persists. I get mail on my PC through iCloud and that's working fine. Mail will drop on the iPhone ocasionally but does not reflect what is on the iCloud server, i.e. deleted on server shows up as unread on app...

Thank you for the very helpful advice, Plinss. It has provided some quite useful background information for resolution options for iOS 18.x users. I can understand how many users would be confused about the issue, and it may well be that in many cases the problem is not directly an Apple fault and could be attributed to various server configurations around the world. Nonetheless, the problem has clearly arisen in the main part since the ios 18 update. If it means that Apple needs to accommodate a wide range of mail configurations in its updates, then surely that needs addressing. It should not be the responsibility of individual users to resolve issues arising from product updates. Australia has quite strong legislation relating to products and services that are not fit for purpose and it may well be that this situation is approaching a tipping point where this problem will trigger some action.

Taco Bob wrote:

…

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

…

I don't think what you excerpted is commented out, and also, this is not the section that defines the separator.

Here is the section from 10-mail.conf. It is commented out on my installation. I do not have a separator defined, and the installation has worked as expected up until 18.x. and continues to work with macOS mail and other MUAs.

mx:~$ sudo dovecot -n |grep separator

mx:~$ sudo dovecot -n |grep namespace

namespace inbox {

mx:~$

#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 =

From what I see in the dovecot documentations, it will use "." as a separator if none is defined.

namespace/separator

• Default: ‘.’ for Maildir; ‘/’ for other mbox formats
• Values: String

Specifies the hierarchy separator for the namespace.

The separator is a single character, which can’t then otherwise be used in folder names.

The commonly used separators are . and /, but other separators can be used as well. For example ^ is less likely to be found in normal folder names.

Recommended value is to leave it empty and accept the default value.

Example:

namespace {
  separator = /
}

See also

Hierarchy Separators

From dovecot.org