I created a VM with Ubuntu 16.04.3 and installed Apache2.4 on it.
My Nextcloud instance is working fine but I want to use the Collabora too.
So I used the tutorial from nextcloud and installed the docker container.
This is the error message I get when I tried to open an doc file:
Error richdocuments GuzzleHttp\Exception\RequestException: cURL error 60: SSL certificate problem: unable to get local issuer certificate