Collabora install but show Could not establish connection to the Collabora Online server

i have setup nextcloud and collabora on same server different domain name but there is problem with dns name resolve. i have 4 public ip and 3 of them is olny for nat and 3 ips are lan pool of isp .when i install collabora there is an error dns lookup failed the external ip this server is not same as the A-record & Wan ip and dns record duos not match.this happen when using ddns for example.

please help me to configure collabora with nextcloud

You should ask your DDNS provider about how to set DNS record, and make sure your server can be visited, firstly.

thank for replay…
both domain is working and resolve same ip add when you ping but the issue is that the i setup arp-proxy ip pool for next cloud and default pubic ip if different from this ip when system connect to internet its show different public add

Sorry, I am not familiar with arp-proxy.

I am not sure if the frp reverse proxy tool can help you.

you can vist your callabora server like this url to check if it is available:
If you can see a box asking you to longin, then the callabora server is available.

By the way, your sentence is too long to read. You may try to use google translate.

Thanks @berlin2 for the update
I too faced the same issue.
I was upgrading first in development environment.
The reverse proxy seems perfect , I’m able to open admin.html from the ui collabora config
“Could not establish connection to the Collabora Online server.” still persist
However from curl it gives result.

From another of your post says collabora 3.6.0 has bugs and it is rectified in 3.7 but it is still a nightly build package.
Awaiting for a stable one.