"Could not open folder"

[Hedaja]

Steps to reproduce

1. Open the Mail app
2. Try opening certain email folders (like inbox)

Expected behavior

Display all messages in the folder

Actual behavior

No emails shown but a "Could not open folder" message is being displayed

Mail app version

5.11.3

Nextcloud version

33.0.8.2

Mailserver or service

No response

Operating system

mutliple Linux Distros and WIndows 10/11 with Chromium and Firefox

PHP engine version

Other

Nextcloud memory caching

No response

Web server

None

Database

MySQL

Additional info

I think it could be related to formatting/specialties of certain emails.
The folders can load if the certain emails are excluded for example by searching of keywords or adjusting the date range.
It seems to effect most emails by one sender but also multiple other emails and I haven't seen a clear pattern yet.

All emails work fine when I use Thunderbird to access my email account. So it doesn't seem to be an issue with the mail server.

I isolated one email that breaks things and that is not too much of a privacy issue and will attach it here.
Any other good steps I can take to help debugging?

PHP 8.4.12

[Hedaja]

Issue email.eml

[GretaD]

Hello, thank you for reporting this issue. There is a potential fix for a similar issue like yours: #12654

It would be helpful if you could review or test that PR to see if it works.