Enketo seems running but deployment gives "link missing" and form preview returns "Server Error (500)"

[datarange]

We are not able to deploy form on our self-hosted KoboToolbox.
Here are the screenshot that show the issues :

Form preview, with server response header

The system health shows no problem :

I was searching for the similar questions, it seems that problem may be caused by a communication issue between the reverse proxy and the internal server who is listening on port 8080, this premise can be endorsed by the fact that Kobotoolbox keep showing Waiting for environment to be ready. It can take a few minutes and never outputs the successful startup message.

Any direction pointed out is appreciated.
Thanks

[Kal_Lam]

@datarange, maybe this post discussed previously should help you solve your issue:

Kobo form could not open

We install kobo on our own server. The only problem we are having is that the open button to open the form is not working and the copy button disappears. [Screenshot from 2020-01-07 09-36-03] Can someone please help

[datarange]

Thanks @Kal_Lam , as indicated here
extra_host should be uncommented for ee, kf and kc in the frontend image
docker-compose.frontend.override.yml

Now the issue is gone.

[Kal_Lam]

@datarange,

[nolive]

Would you mind to share your kobo-install .run.conf (hide any secret credentials).
Usually, when extra_hosts is commented is because you choose the option with the private DNS on your local network. So the domain names resolution is happening thanks to the DNS server.