Unable to view Email images

Your software
My Mautic version is: 3.3.4
My PHP version is: 7.3.30
My Database type and version is:

Your problem
My problem is:
When I upload an image to an email the upload seems successful, but the image cannot be accessed afterwards.
This was working before and it stopped working without us doing any changes.
This is displayed right after the upload:

When I try to open the uploaded image:

These errors are showing in the log:
No errors

Steps I have tried to fix the problem:

What permissions are set on the images directory?

Thank you for the reply EJL!
We use Kubernetes and the folder is configured as follows in a yaml file:

- name: mautic-emailmarketing
  mountPath: /var/www/html/mautic-images
  readOnly: false
  subPath: images

These are the permissions of the folder:
drwxrwxrwx 2 root root 0 Jun 13 2019 .

Why root? I don’t think your apache / nginx is ran as root, right?