Websocket 426 Error, with LiveView

Phoenix Forum Questions / Help
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Hi,

I have developed some things with LiveView. All is working on my machine (how many times I would have said that …), and also on the test server. The problem is that it is not working on the production server. If I open Firefox’s developer tools, I can see an error message:

Firefox can’t establish a connection to the server at wss://mydomain.com/live/websocket?vsn=2.0.0

And after that, an HTTP failed request with code 426 Upgrade Required.

Do you know what am I doing wrong?

Thanks in advance.

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:wave:

Is your production box behind a load balancer / reverse proxy of any kind? Maybe it doesn’t allow upgrade requests through, then cowboy would respond with 426 probably, since it expects one. But that’s just speculation.

3 Likes
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Nop. The connection goes directly to Cowboy.

I have done some tests, finding out that when I configure Phoenix with server IP instead of domain and access directly to that IP, all works without problems.

Could be related to https?

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Can you post this configuration here?

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Never mind. I find out that there is a Caddy reverse proxy configured. After configuring it with proper WebSockets configuration, all is working fine.

Thanks for your help.

1 Like