Xlsx links no longer open in OnlyOffice

Good morning
I have a NextCloud installation on a dedicated server.
I have an installation on another dedicated server of an OnlyOffice server.
It worked since the migration 3 months ago to version 27, when you clicked on an xlsx data file stored on Nextcloud, it opened it in OnlyOffice.
For a few days (no server manipulation, no parameter modification) when I click on an xlsx or docx file, it offers to download it !
And I no longer have a solution to open it (excludind download, make a local modifiation and upload it on the server).
On the other hand, those which are already open in a tab, when you click on the tab, they refresh and you can work with them through OnlyOffice!?
The problem seems to be an access problem I don’t think it comes from OnlyOffice (since it works for those already open!)
Does anyone have a lead?
Thanks in advance !