404 error when trying to see pictures

Summary

Half of our Team cannot see any pictures anymore in the issues.
We cannot really figure out why it happens. It is in any issues. They all are Editor but we did not make any change in their options.

Steps to reproduce

Click on any issue which has a picture.

What is the current bug behavior?

People cannot see the picture :

If they click on it :

What is the expected correct behavior?

We should see directly this picture : (What you should see instead)

Relevant logs and/or screenshots

(Paste any relevant logs - please use code blocks (```) to format console output, logs, and code as it's tough to read otherwise.)

Output of checks

This bug happens on https://gitlab.zei-world.com/

Results of GitLab environment info

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:env:info)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production)

Results of GitLab application Check

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)
(we will only investigate if the tests are passing)

Possible fixes

(If you can, link to the line of code that might be responsible for the problem)