Hi guys I have installed nextcloud and collabora online CODE on the same stretch perfect server and so far so good, I can edit my file from nextcloud with CODE. Now I've installed a second nextcloud on an other server and can't connect to my collabora on the first server I assume it's related to firewall or iptables settings, but I couldn't find a safe answer by myself and online. Here some more detail on my stretch perfect server I have cloud.mydomain.net where nextcloud is working like a charm office.mydomain.net set up using collabora online debian package (see here) and with a reverse proxy (see here) so I can access to collabora here office.mydomain.net for both domain I have set up an SSL certificate using ISPC interface (I thus have follow only some of the reverse proxy and ssl certificates tuto above) in nextcloud's settings, I have set that collabora URL is https://office.mydomain.net:443 At this stage I can edit my file from nextcloud with collabora - yay ! Now, I have an other server on which I set a domain cloud2.myotherdomain.net and installed nextcloud. Nextcloud is working like a charm, and I have defined that collabora url is also https://office.mydomain.net:443, however when I try to edit a file from nextcloud, it tries to open the file, but end up saying tha it can't to connect to collabora... I assume the issue comes from my perfect server settings, especially firewall, but I can't find how to be sure that any inbound and outbound request from a given domain (cloud.myotherdomain.net) or IP are accepted ? And if so, what could prevent my stuff to work ? Thank's in advance for your guidances.