Admin panel cannot be loaded

Describe the bug

I cannot manage to reach the admin panel : when I input the URL specified by the "administrator docs" section ("https://emrys-vision.fr/snappymail/app/?admin", I get the following error message: "An error occurred. Please refresh the page and try again. Network response error: 500".

This is a very recent problem that is not resolved either by reinstalling the app or even completely rebuilding my VPS server. I have installed SnappyMail on Yunohost many times already, and I never got this problem until yesterday.

What I have already tried:

Using another browser
Connecting from another IP address
Moving the app to its own subdomain
Reinstall the app
Rebuild the server from scratch

I have activated Level 7 logging and this is the only thing I can see in the log file:

[2024-03-02 16:44:36.640][7e5d3df3] [INFO]: Memory peak usage: 2MB
[2024-03-02 16:44:36.640][7e5d3df3] [INFO]: Time delta: 0.0025389194488525
[2024-03-02 16:44:36.677][2f9e1d2c] [INFO]: Memory peak usage: 2MB
[2024-03-02 16:44:36.677][2f9e1d2c] [INFO]: Time delta: 0.0015590190887451
[2024-03-02 16:44:37.541][ae675fa3] [INFO]: Memory peak usage: 2MB
[2024-03-02 16:44:37.541][ae675fa3] [INFO]: Time delta: 0.0021910667419434
[2024-03-02 16:44:37.582][e855228a] [INFO]: Memory peak usage: 2MB
[2024-03-02 16:44:37.582][e855228a] [INFO]: Time delta: 0.0017919540405273
[2024-03-02 16:45:23.328][3645ee6b] [INFO]: Memory peak usage: 2MB
[2024-03-02 16:45:23.328][3645ee6b] [INFO]: Time delta: 0.034564018249512
[2024-03-02 16:45:23.373][e8f84fcf] [INFO]: Memory peak usage: 2MB
[2024-03-02 16:45:23.373][e8f84fcf] [INFO]: Time delta: 0.005742073059082

Misc remarks:

My domain settings are OK and Yunohost diagnostics only exhibit minor and unrelated warnings
The client side of the app works normally, only the admin panel fails to load
Changes made in the application.ini file are taken into account

Context

Hardware: VPS at OVH
YunoHost version: 11.2.10.3 (stable)
I have access to my server: SSH + webadmin + online KVM at OVH
Are you in a special context or did you perform some particular tweaking on your YunoHost instance?: no
- If yes, please explain: I use a typical install, either in a subdomain or not
Using, or trying to install package version/branch: only using the Yunohost store
If upgrading, current package version: 2.35.2~ynh1

Steps to reproduce

Install the app through the Yunohost store
Try to launch the admin panel through the provided URL

Expected behavior

The admin panel should be displayed.

Logs

The only available log is from the installation process:

metadata: 
  args: 
    app: snappymail
    force: False
    label: undefined
    no_remove_on_failure: False
  ended_at: 2024-03-02 13:13:14
  env: 
    YNH_APP_ACTION: install
    YNH_APP_ARG_DOMAIN: emrys-vision.fr
    YNH_APP_ARG_INIT_MAIN_PERMISSION: visitors
    YNH_APP_ARG_PATH: /snappymail
    YNH_APP_BASEDIR: /var/cache/yunohost/app_tmp_work_dirs/app_im0h428f
    YNH_APP_ID: snappymail
    YNH_APP_INSTANCE_NAME: snappymail
    YNH_APP_INSTANCE_NUMBER: 1
    YNH_APP_MANIFEST_VERSION: 2.35.2~ynh1
    YNH_APP_PACKAGING_FORMAT: 2.0
    YNH_ARCH: amd64
    YNH_DEBIAN_VERSION: bullseye
  error: None
  interface: api
  operation: app_install
  parent: None
  related_to: 
    - app
    - snappymail
  started_at: 2024-03-02 13:12:50
  success: True
  yunohost_version: 11.2.10.3
metadata_path: /var/log/yunohost/categories/operation/20240302-131250-app_install-snappymail.yml
name: 20240302-131250-app_install-snappymail

YunoHost-Apps / snappymail_ynh