Html emails are shown in a tiny preview iframe even if there is a lot more space that the iframe could use

[xX-MrN0b0dy-Xx]

Steps to reproduce

1. Deploy a new Nextcloud instance from scratch and perform preliminary configuration
2. Install Mail app, it will install "Mail 5.10.3" (latest version)
3. Open the app and configure a client
4. Open an html mail from the inbox or any folder

Expected behavior

Correctly show the mail in an iframe utilizing entire available space

Actual behavior

Only a small portion of vertical available space is used for the iframe

Mail app version

5.10.3

Nextcloud version

33.0.5

Mailserver or service

Mailcow

Operating system

Linux 6.18.29+rpt-rpi-2712 aarch64

PHP engine version

8.4.22

Nextcloud memory caching

No response

Web server

Apache

Database

MariaDB 11.8.8

Additional info

I found out that this happens only on new instances configured from scratch with Nextcloud version 33.0.5 and Mail 5.10.3. I have another instance that was running "Mail 5.9.2" and after updating it, the problem isn't showing up (same client, same mail used for testing).

So, I think this has something to do with preliminary config files created installing latest mail version, that fixed #13028 .

Moreover, I think that something like this probably already happened in the past, see #3696 .

Browsers utilized:

• Safari 26.5 (21624.2.5.11.4) MacOS 26.5.1
• Firefox 152.0.1 (aarch64) MacOS 26.5.1
• Firefox 152.0.1 x86 Fedora KDE 44 rpm version

[odzhychko]

@xX-MrN0b0dy-Xx Thank you for reporting the issue.

I wasn't able to reproduce it. Could you please do the following to help me reproduce it:

• Share a mail that is displayed wrongly as .eml. Either here or via email to oleksandr.dzhychko@nextcloud.com
• Share what you have set under "Mail settings > General > Appearance > Show all messages in thread"

[KOEWADO]

I can confirm this behavior.
I testet it on 33.0.6 with mail version 5.10.4 / 5.10.5

There is no difference between "Mail settings > General > Appearance > Show all messages in thread" on or off. Testet on Browser: Chrome, Edge, Brave, Firefox Testet with several mails

[xX-MrN0b0dy-Xx]

@odzhychko

• Share what you have set under "Mail settings > General > Appearance > Show all messages in thread"

"Mail settings > General > Appearance > Show all messages in thread" is not influent, I tried both every time completely clearing browser cache.

Also "Mail settings > General > Layout" is not influent.

• Share a mail that is displayed wrongly as .eml. Either here or via email to oleksandr.dzhychko@nextcloud.com

See the attached .eml mail that is one of the impacted ones, but actually I see that all mails are affected.

Re_ [nextcloud-mail] Html emails are shown in a tiny preview iframe even if there is a lot more space that the iframe could use (Issue #13160).eml

Also, to help trying to recreate the problem, I'll try to share as much info as possible, in the hope to be more helpful that annoyingly verbose. On top of issue description above with host detail, this is my compose:

name: nextcloud


services:
  app:
    image: &image nextcloud:33.0.5-apache
    container_name: nextcloud
    restart: unless-stopped
    ports:
      - 8888:80
    depends_on:
      - db
      - cache
    environment: &environment
      TZ: Europe/Rome
      PHP_UPLOAD_LIMIT: 2G
      PHP_MEMORY_LIMIT: 1G
      APACHE_BODY_LIMIT: 0

      NEXTCLOUD_TRUSTED_DOMAINS: "${TRUSTED_DOMAINS}"
      NEXTCLOUD_UPDATE: 0
      NEXTCLOUD_INIT_HTACCESS: true

      # db
      MYSQL_HOST: db
      MYSQL_DATABASE: "${DB_NAME}"
      MYSQL_USER: "${DB_USER}"
      MYSQL_PASSWORD: "${DB_PASSWORD}"

      # cache w/ redis
      REDIS_HOST: cache
      REDIS_HOST_PORT: 6379

      # mail sender
      SMTP_HOST: "${MAIL_HOST}"
      SMTP_SECURE: starttls
      SMTP_PORT: 587
      MAIL_FROM_ADDRESS: "${MAIL_FROM_ADDRESS}"
      MAIL_DOMAIN: "${MAIL_DOMAIN}"
      SMTP_NAME: "${MAIL_USERNAME}"
      SMTP_PASSWORD: "${MAIL_PASSWORD}"

    volumes: &volumes
      - ./config:/var/www/html/config
      - ./data/app/main_folder:/var/www/html
      - ./data/app/user_data:/var/www/html/data
      - ./data/app/custom_apps:/var/www/html/custom_apps


  cron:
    image: *image
    container_name: nextcloud_cron
    entrypoint: /cron.sh
    restart: unless-stopped
    depends_on:
      - db
      - cache
      - app
    environment: *environment
    volumes: *volumes


  db:
    image: mariadb:11.8
    container_name: nextcloud_db
    restart: unless-stopped
    expose:
      - 3306
    environment:
      MARIADB_ROOT_PASSWORD: "${DB_ROOT_PASSWORD}"
      MARIADB_DATABASE: "${DB_NAME}"
      MARIADB_USER: "${DB_USER}"
      MARIADB_PASSWORD: "${DB_PASSWORD}"
    volumes:
      - ./data/db:/var/lib/mysql
      - /etc/localtime:/etc/localtime:ro
      - /etc/timezone:/etc/timezone:ro #for Debian based images


  cache:
    image: redis:latest
    container_name: nextcloud_cache
    healthcheck:
      test: ["CMD-SHELL", "redis-cli ping | grep PONG"]
      start_period: 20s
      interval: 30s
      retries: 5
      timeout: 3s
    restart: unless-stopped
    expose:
      - 6379
    volumes:
      - cache_data:/data
      - /etc/localtime:/etc/localtime:ro
      - /etc/timezone:/etc/timezone:ro #for Debian based images

volumes:
  cache_data:

And these are all the bash commands I run:

mkdir config data/{app,db} -p
sudo chown -R www-data:www-data data config
sudo docker compose up -d

After preliminary config, where installation of suggested apps is skipped, from inside container I run:

./occ app:install calendar
./occ app:install contacts
./occ app:install mail
./occ app:install tasks
./occ config:system:set default_phone_region --value="IT"
./occ config:system:set maintenance_window_start --type=integer --value=2
./occ db:add-missing-indices

I can't test a new test environment deploy right now, I'll do it during lunch time (CEST).

Edit: I tried to update my instance to "Mail 5.10.5", but nothing seems to be changed.

[odzhychko]

Also, to help trying to recreate the problem, I'll try to share as much info as possible, in the hope to be more helpful that annoyingly verbose. On top of issue description above with host detail, this is my compose:

Better verbose then not enough. Thx especially for the full env config, I will try it out and come back to you.

[xX-MrN0b0dy-Xx]

I tried to deploy on a x86 (Fedora 44 KDE) machine a new test instance following exactly my instructions, connecting to same mail client and ofc the mail version that has been installed is the lastest one (5.10.5). Surprisingly, the problem is not present anymore. Just to be extra sure, I also tried to setup a new instance from a raspberry pi5 similar to the one I use as main unit, with same kernel. Also there, problem is not present anymore (I am aware that mail is a PHP app or anyway arch agnostic, but I had that extra couple of minutes to test it and I did it).

Up to know, the facts I was able to gather are:

• If you have an old nextcloud instance with mail app version prior to 5.10 and you update to 5.10.x, you're good
• If you configure a brand new instance of nextcloud and install mail app with version >= 5.10.5, you're good

So, I have a question for @KOEWADO : is your instance almost new or anyway, did you installed mail app from scratch with version 5.10.3 or anyway after 5.10 and before 5.10.5?

If the answer is yes, we can add to the list of facts the following:

• If you configured an instance in the past few weeks and first version of the app was 5.10 < x < 5.10.5, the bug shows up

Main problem is that, as of now, I tried to uninstall mail app, clean cache, compose down and back up but after reinstalling a brand new version of mail the bug is still there... (I did not touch the database).

I also tried to update nextclout to latest 33.0.6, but this didn't fix it.

[KOEWADO]

So, I have a question for @KOEWADO : is your instance almost new or anyway, did you installed mail app from scratch with version 5.10.3 or anyway after 5.10 and before 5.10.5?

Yes, i had install a prev version of the mail app (think it was 5.10.3) -> got this problem
Update today to 5.10.5 -> always got this problem

Maybe some older files not included in update stays on the server