Hi all,
I searched already a lot and found many reports with the same error message but never a solution which works for me 
I installed Nextcloud AIO on my Synology NAS, following this documentation: Nextcloud AIO installation guide for Synology NAS
To avoid as much sources of error as possible I disabled the firewall from Synology completely. Nextcloud works great:
- I can connect to Nextcloud
- Install additional apps from the app store
- Talk HPB works
- TURN server works
So I would say network, including the reverse proxy and dyndns works fine as it seems that not only the connection to Nextcloud itself works but also to the additional containers like the Talk HPB.
Still Collabora always throws this error:
Could not establish connection to the Collabora Online server.
Failed to connect to the remote server: cURL error 28: Operation timed out after 5002 milliseconds with 0 bytes received (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) for https://<my-domain>/hosting/discovery
I already tried to set the “wopi allowed hosts” to “0.0.0.0/0” via occ (because the web interface is not availble due to the early error) with no success.
I also tried to add the mastercontainer IP, which as far as I understand should be the entry point for all request and than redirect to the correct container, to /etc/hosts of the nextcloud container to allow a direct internal connection from the Nextcloud container to all other containers with the same domain name.
172.18.0.2:8080 <my-domain>
Still the error is always the same. Any idea what else I could try?
