Download of attachment in digital print shop fails

[connium]

Describe the Bug

A region manager reported that they cannot download attachments of applications for the Ehrenamtskarte Bayern but are shown an error message instead.

Steps to Reproduce

1. Go to 'https://bayern.ehrenamtskarte.app/'
2. Log in as region administrator
3. Go to 'Eingehende Anträge'
4. Expand the card for an application with an attachment
5. Click on the attachment to download it
6. See error

Expected Behavior

When clicking on the attachment, it should download the file and no error should be shown.

Additional Information

OS: Windows 11 (Version 23H2 Build 22631, 4890)
Browser: Edge

bayern.ehrenamtskarte.app-1739950871506.log

[f1sh1918]

Really weird error. Not sure how they can get an CORS issue here.

 Access to fetch at 'https://api.entitlementcard.app/application/bayern.ehrenamtskarte.app/29082/file/0' from origin 'https://bayern.ehrenamtskarte.app' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
JsonFieldElemental.tsx:51 
            GET https://api.entitlementcard.app/application/bayern.ehrenamtskarte.app/29082/file/0 net::ERR_FAILED 307 (Moved Temporarily)

I can not reproduce this. For me it looks like it relies on their local network configuration.
You shouldn't get an CORS error here. CORS blocks the fetching here but the file is on the server
Has anyone some ideas how this can happen on our production environment. Maybe @svenseeberg ?