How can I resolve the 'POSIX 96' error on my iPad?

1kc2008 wrote:

Since upgrading to iOS 18 I and many others have had certain mail accounts non functional only on iPads with the posix 96 error. Apple is aware and with the latest update 18.3.2 the issue continues.

Posix 96 errors are connectivity errors. They are almost always caused by a misconfigured VPN.

Do you have a 3rd party VPN installed, even if you are not using it? If so, delete the VPN profile in Settings/General/VPN & Device Management/VPN. Don't just turn it off; delete the profile. If that fixes it, you can try reinstalling VPN. However, VPN actually reduces your privacy, it does not enhance it, so you may want to rethink the reason you use VPN

baggian wrote:

TLS is not a VPN. TLS is an encryption layer at the "stream" level, not the low level network level like a VPN.

TLS can absolutely provide a VPN. But sure, you can absolutely make the case that there are uses for over-hyped added security, with un necessary overhead, and perfectly implemented to capture and collect users’ personally-identified metadata. I mean, who would possibly want robust end-to-end encryption provided by TLS, when they can route all their personally-identified traffic through data-mining vendors.

As for the issue here, its cause is unclear. one potential cause of routing issues is add-on “coffee shop” VPNs, which can and do alter network routing. Sometimes with unexpected or undesired results beyond data collection and privacy issues.

You are using a VPN. TLS, in this case.

Add-on “coffee shop” VPNs can also get (further) tangled, even when not active.

Where the problem exists here — in the mail server and its certificates, in TLS, or in the Apple mail client— Apple is best positioned to determine and resolve.

So, do we know anything more? The really interesting threads on this have been locked...

Some said it happened when Dovecot was being used as the imap server and a separator of a backslash \ was being used. Other's claimed VPN issues or similar.

On my iPhone, which I finally upgraded to iOS 18 (18.3.1) a few days ago, I get this but if I retry it usually works... The error is listed as "POSIX 96". I'll see an error at the bottom but when I touch the the error and it retries it works.

On my Mac, which is a new Mac using Sequoia 15.3.2, which replaced an older Intel iMac running a major version or two older macOS, I sometimes get the download of new mails freezing and nothing short of a reboot of the Mac will fix it. Killing email and restarting it leaves it at the exact same stuck place. I've not seen an error code for it.

My accounts happen to be served by a Dovecot instance (and have been for some 12-13 years) and I don't have a \ as the separator. This whole problem is getting annoying. Luckily my mail customers haven't complained to me yet.

namespace inbox {

  type = private

  prefix = INBOX.

  separator = .

  inbox = yes

}

TLS is a technology to encrypt a stream. It can possibly be used to create a VPN. TLS is not a VPN. It's typically used to encrypt an application connection, for example, to an SMTP or IMAP connection, or to an HTTP server, or an XMPP server. It's definitely an important technology. However, it is not a VPN. A VPN encrypts the low level network level.

But that is neither here nor there. In my case no VPN is involved, though the IMAP connection is encrypted, and has been for a decade. I was wondering if there have been any updates on this issue. Lots of reports of this error with Mail on iOS / iPadOS and maybe macOS mail? The more interesting threads about this have been locked so I asked on one of the unlocked threads.

TLS is not a VPN. TLS is an encryption layer at the "stream" level, not the low level network level like a VPN.