Bug when creating a new Collabora Online file from NC21 web interface

Collabora Online files created from NC21 web interface can’t be opened next, generating the error “Failed to load the document. Please ensure the file type is supported and not corrupted, and try again” (see screenshot in attachment).

This bug was not present in my NC 20 instance and happened since I have upgraded to NC 21.

My setup:
Nextcloud version : 21.0.1
PHP version : 7.4
Collabora Online: 4.0.4

Steps to replicate the bug:

  1. Create a new Collabora Online file (whatever type) through the NC web-page (+ icon)
  2. The file is automatically opened by Collabora Online and generates the error message


I have the same problem. But the error message appears when I open an existing document as well. I’m using NC and Collabora from docker collabora/code (6.4. as I think). How can I find out the running version of collabora? Nextcloud can access the collabora server. and the collabora site says “ok”.

Are you using smb as external storage?

Thank you for your reply. No, I don’t use external storage.

I confirm that I don’t use an external storage too.