My guess is that the problem is that one end or the other has a different idea of the transfer protocol for the content of messages. One end is listening, but the other end is not sending or also listening.

If you can set up a Wireshark test bed you can easily see who is waiting for who.

Good luck.

On 2/5/25 10:20, Zieseniss Peter via dovecot wrote:

Hello All, i hope everyone is well!

i have a rather irksome and pressing issue that i can't seem to resolve..

This happens only on iOS devices..

Specifically, the problem is that the content of messages seems to timeout when it loads either when you open a message, or when you hit reply or forward, or whatever.. The email appears to load, but the content simply never shows up, leaving only a wheel that says 'Loading' Please see a screenshot of what it looks like: https://zconsulting.net/_stuff/dovecot-ios-loading.jpg

This happens on all iOS devices (at least 18), many different versions from the most current down to iOS 16.. This has been happening for at least 2 years, and it happens about 50-80% of the time when interacting with an older message (more than 6 months old) Mail on macOS, Thunderbird on Windows, and RoundCube on the server all work perfectly.. Note that most of these accounts have at between 12GB and 80GB (that's the extreme case) of email..

The server is: Dedicated 4-Core Xeon, 16GB RAM, 512GB NVMe SSD AlmaLinux release 8.10 (Cerulean Leopard) Dovecot 2.3.21.1 Exim 4.98

Here's what i've tried: On the server, i installed FTS-Xapian On the server, i set mail_max_userip_connections=512 On the clients, i disabled all email privacy settings and disabled iCloud mail

The problem is that i really can't figure out what the issue is, but this seems to be a very common issue between Dovecot and iOS, judging by the amount of similar questions i see on g00gle, but no useful answers (example here <https://dovecot.org/mailman3/archives/list/dovecot@dovecot.org/thread/6YCEVZVP3WMODHWLTDJPMFSSFJ6EC7YD/#7EAYFBU2HUMSPOLCNKJIDJCE2IRZK7YC>).. It certainly seems like the iOS mail client is timing out when receiving the body of these older messages, but i don't see anything useful in the logs..

Please help! Any suggestions are welcome!

My client is about to crucify me over this..

Thank You All in advance! Sincerely, Peter