Mail not working on iPhone after iOS 18 Update

It looks like the OP is using Zimbra (which uses the Postfix as its MTA). For those who use Postfix, but especially for those using Zimbra, you may want to have your admin look at ZBUG-4531 and this post https://forums.zimbra.org/viewtopic.php?t=72998. Basically, whatever Apple changed in Mail from iOS 17 to iOS 18, it's causing Zimbra/Postfix to generate egregiously long list of conditions for IMAP queries on the back-end, causing accounts to lockup for minutes if not hours while the query is running. While Zimbra/Postfix should definitely be limiting max conditions, Apple absolutely needs to do a better job of debugging and testing. Really unacceptable for a trillion dollar company with the kind of resources they have to failed like this and then proceed to not fix it.

I have the same problem both on my IPhone and IPad. Is Apple working on this or …

“Basically, whatever Apple changed in Mail from iOS 17 to iOS 18, it's causing Zimbra/Postfix to generate egregiously long list of conditions for IMAP queries on the back-end, causing accounts to lockup for minutes if not hours while the query is running”

Postfix is an SMTP server and has nothing to do with IMAP

In my case it is definitely a certificate issue. The IMAP (Dovecot) cert is a public trusted cert and is installed as a profile in the device, along with the intermediate and CA certs (CA is trusted).

Calling the IMAP connection from an external (WAN) connection using the domain (as in the cert) works fine.

Calling the IMAP connection from within the LAN (using an IP address on the LAN) results in a certificate error.

This happens on iOS 18. It works fine on iOS 17.

I cannot seem to find a way to explicitly allow trust of the IMAP certificate when used with an IP address rather than the cert domain.

For me, so far the 18.3 update appears to have fixed my IMAP problem with Apple Mail. All mail folder contents and attachments are now fetched right away instead of locking up for some considerable time, as was the case previously. I did the update to 18.3 but did not open Mail for several hours, to find it working fine. So far.

I use a Dovecot IMAP server on my NAS, Mail accesses it via LAN IP address via a non-secure connection, if that makes any difference.

Hi guys

Here's a bit of good news that may be useful to some of you:

Since iOS18 my ZIMBRA business mail account no longer synchronizes in IMAP, as many here do.

My admin suggested I use ActiveSync (Exchange account) instead of IMAP. The good news is that it works fine in iOS 18.3.

After downloading 18.3 to my IPad email is still not working and on my iPhone attachments can’t open. Anyone knows when Apple will fix this

I just updated to iOS 18.3 today and mail is still not pushing to the Apple mail app. I’ve submitted several tickets and no response from Apple.

Update: After restarting my phone after the iOS 18.3 update my email is being pushed to my phone in the 15 min increments however there is no ping sound, just banner notifications. I did check the sounds and everything is on as it should be. Any suggestions??

Knowing what I was likely to be letting myself in for, I decided not to update my phone but update ipad for a test.

I run my own mail server with a self signed SSL certificate.

Updated to iPadOS18.3

Deleted Mail account.

Set up Mail account with working settings from iPhone on iOS 17.7.2

I was asked to review details and trust for my certificates which I did.

Opened Mail app, all emails visible and readable.

Replied successfully.

As soon as Mail app checked for new mail I got:

The mail server X is not responding. Verify that you have entered the correct account info in Mail settings

Unable to create a secure connection to the server (“bad certificate format@ -9,808)

Set up outlook connection to

my account without issue!

For those who manage their own mail server using self signed certificates there are a number of options to move to LetsEncrypt certificates which fixes the problem. This is a high level recipe for Amazon Linux 2.

Follow this :

https://gist.github.com/mrothNET/cb6f313e9cbe896f3e0fdec80ad2f3fa

Points to note - I also run https on this server to I had to stop the service, get the certificate and then restart the service.

I didn’t do the bit for cli.ini for auto-renewal, but read this article instead:

https://stackoverflow.com/questions/42300579/letsencrypt-certbot-multiple-renew-hooks

I followed the answer for Centos/Amazon Linux.

I had to enable the certbot-renew.timer service

I then edited /etc/sysconfig/certbot and added a PRE_HOOK to stop httpd, POST_HOOK to start httpd and a DEPLOY_HOOK to restart postfix and dovecote (similar to what was posted in the first article for cli.ini) Don’t forget to keep or add the command line switches (eg. —pre-hook) that are in the examples shown in the file

Obviously I don’t know if the renew will work as it takes a bit of time, but after the restarting of dovecot and postfix in the first article, mail started working again.

Not particularly useful if you already have a valid certificate for the mail server.

I already have a Digicert valid mail server cert, for access from external networks. However on the LAN, the mail server is accessed using its IP address. So the cert checking fails in the iDevice, however if explicit trust of the mail server cert was allowed when using the IP address then it would pass.

Set up local DNS to point the external address to the IP address may solve your problem

It looks like everybody is just swinging in the dark and replying with anything that pops up in their head while they’re trying to sober up let’s read what’s been tried not keep sending all these repeat emails

Still not working after applying update 18.3.1. Come on Apple. Please fix this issue. Many people cannot access their email accounts!!