Onlyoffice can't open file

I’ve updated to Nextcloud 18 with which Onlyoffice come preinstalled.

So when I create, for example, a .docx file, Onlyoffice launched up, but then I have this pop-up which just say error.

Here is the screenshot:

Did you ever get this message ? How can I solve this.
Thanks in advence

NB: Also, I’m running Nextcloud with docker.

Also, I’m looking at the Nextcloud’s logs and nothing show up. Is there another logs for the onlyoffice server ?

thats not correct if you update…
you’d need to install community document -app (or similar) manually first… and then oo-connector app.

Can you be a bit more precise on the steps that I should do

Go to Apps, select Community Document Server, download and install it, after that download an install OnlyOffice App.

Okay, I’ve done it twice but now I found this in my log:

Here are the raw error:

{"reqId":"w4ECJoE5nCJKCpuDMkDI","level":3,"time":"2020-02-23T20:54:13+00:00","remoteAddr":"172.20.0.3","user":"Aurnytoraink","app":"PHP","method":"POST","url":"/settings/apps/enable","message":"fclose(): supplied resource is not a valid stream resource at /var/www/html/custom_apps/documentserver_community/lib/Document/FontManager.php#66","userAgent":"Mozilla/5.0 (X11; Linux x86_64; rv:73.0) Gecko/20100101 Firefox/73.0","version":"18.0.1.3","id":"5e52e6768c800"}

{"reqId":"w4ECJoE5nCJKCpuDMkDI","level":3,"time":"2020-02-23T20:54:13+00:00","remoteAddr":"172.20.0.3","user":"Aurnytoraink","app":"PHP","method":"POST","url":"/settings/apps/enable","message":"stream_get_contents(): supplied resource is not a valid stream resource at /var/www/html/custom_apps/documentserver_community/lib/Document/FontManager.php#67","userAgent":"Mozilla/5.0 (X11; Linux x86_64; rv:73.0) Gecko/20100101 Firefox/73.0","version":"18.0.1.3","id":"5e52e6768c74c"}

You know? The community document server only supports running on x86-64 Linux servers.

Did you see this

I know, I running on Nextcloud on a 64bits Linux version.

As I said, I do not use FreeBSD. And this post pretty much doesn’t show anything.
I tried to report the issue on Github and I saw that I wasn’t the only one in this situation.