Document server connection OnlyOffice 403 forbidden

Hi, it would be great to edit office files online.
Thus, I installed the OnlyOffice Connector and the Community Document Server.
However, when saving the OnlyOffice setting with the supposed document server directory, I get the following notice:
Error when trying to connect (Client error: POST resulted in a 403 Forbidden response: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <style type="text/css"> html, body, (truncated...) )
Any idea?
Nextcloud is 18.06 and PHP 7.4.7
Best regards,


Dear Robert,
I had onlyoffice working for one day exactly after I got the same issue. I did an update and encrypted my files.
I have been adviced to use the docker version of onlyoffice. For me this is no real solution as I have got a lot of webspace but with only a few permissions. Maybe for you?

Another solution was to delete documentserver and onlyoffice and before the reinstallation typing into occ:
config:system:delete only office
config:system:delete documentserver community
As soon as the other user touched anything it broke again, but 'til then it was working.

Maybe someone has another solution? Would be so happy.