Connection error, linked (according to Firefox 66.0.2) to a security question


When I click on the link Firefox displays an error message instead of the expected JPEG image.

The message says : “Secure Connection Failed.
An error occurred while connecting to

  • The page you are trying to view can not be displayed because the authenticity of the received data can not be verified.
  • please contact the owners of the website to inform them of this problem.”

Another test done with the Vivaldi browser: no problem.

What is the solution, since everything worked until now (including Firefox)?


Just checked on both chromium and firefox and seems to be working just fine. Can you confirm?

Hmm. I had the same error with Pale Moon a few hours ago, but it doesn’t appear anymore. Should be fine then.

No problem now (monday, april 8th). Something has been done (I ask whether this is likely to happen again – unspecified failure)?

I think it had to do with nextcloud update to new version and some inconsistency in preview generation. I have made a remark in our update procedure to pay attention to this the next software update and see whether this re-apears and thus needs to be fixed each time right away after an update.