Warning message when opening a document

[Skildor]

Hi, Each time I open a document in redmine I got the following message :

It's a bit annoying, but everything seems to work fine after I close the popup.

I'm using docker for redmine and the document server with Apache on the host as an HTTPS reverse proxy

• Redime 5.1.2
• Onlyoffice docserver 8.0.1.31
• Redmine Pluggin 3.1.0

docservice.log redmine.log

Do you have any idea on how to fix this?

Thanks