ERR_EMPTY_RESPONSE from localhost:8091

[bikemike]

I've installed v9.3.2 through snap and the web UI was working initially. Unfortunately it has stopped working and I'm not sure why. Chrome gives me the following:

http://localhost:8091

This page isn’t working
localhost didn’t send any data.
ERR_EMPTY_RESPONSE

I had also tried to set up https in the settings prior to this but it doesn't work either. I assume it's also an empty response:

https://localhost:8091

Your connection is not private
Attackers might be trying to steal your information from localhost (for example, passwords, messages, or credit cards). [Learn more](chrome-error://chromewebdata/#)
NET::ERR_CERT_INVALID

Is there a place I can look for connection and error logging to see what might be causing this issue?

Thanks!

[robertsLando]

Could you attach application logs please?

[robertsLando]

If you enable FORCE_DISABLE_SSL then the option is hidden from the UI.

Exactly. The reason why you see it on startup for a short time is that it is hidden once I receive the settings from the api call

[bikemike]

Ahh. And that's what @jmgiaever had me do. I see. Thanks! Still wondering how setting the FORCE_DISABLE_SSL fixed my ERR_EMPTY_RESPONSE issue but happy to have the UI back.

[kpine]

Because you were accessing an SSL endpoint using non-SSL, and setting that to true disables SSL. Your configuration forced SSL on due to the snap usage of env var SERVER_SSL, despite the settings.

If you can edit the snap configuration, deleting fields "force-disable-ssl" and "ssl", it should work w/o SSL.

❯ curl http://github.com:443
curl: (52) Empty reply from server

[bikemike]

Where and how is SERVER_SSL set? I don't believe I ever set it. I think I might have selected the HTTPS option in the general settings but querying them in the terminal (sudo snap get -d zwave-js-ui) showed "ssl": false. If it was enabled, wouldn't https://localhost:8091 have worked?

[kpine]

You're not setting it, the snap is. It's a problem with the snap. #3425 (reply in thread)

According to your comment, SSL was working:

Your connection is not private
Attackers might be trying to steal your information from localhost (for example, passwords, messages, or credit cards). Learn more
NET::ERR_CERT_INVALID

Here your problem is Chrome. It doesn't allow localhost connections using self-signed certificates. It works fine in Firefox once you tell it to accept the certificate. You can either create a valid certificate and install it into ZUI, or force Chrome to allow "unsafe" localhost connections: https://communicode.io/allow-https-localhost-chrome/