I am running currently a webserver with ASP.NET Core 3.1 and a Blazor project. Recently when upgrading to .NET 6.0 I encountered (even with a blank Blazor project) some problems with a websocket error message in the browser only when deployed on my webserver (see message below).
Locally (on Windows 11 x64, VS 22 Preview 4) there are no error messages...
Webserver: Debian 10 x64, .NET 6.0 SDK installed, running on NGINX with websockets enabled (reverse proxy).
Do I miss out on something or is it a problem with the current state of .NET 6.0 and NGINX? I already tried to access the webpage locally on the debian server and the same error message occurs.
Help would be much appreciated!
Greetings!
Error messages within order:
Information: Normalizing '_blazor' to 'http://192.168.178.35/_blazor'.
blazor.server.js:1 WebSocket connection to 'ws://192.168.178.35/_blazor?id=wnPt_fXa9H4Jpia530vPWQ' failed:
Information: (WebSockets transport) There was an error with the transport.
Error: Failed to start the transport 'WebSockets': Error: WebSocket failed to connect. The connection could not be found on the server, either the endpoint may not be a SignalR endpoint, the connection ID is not present on the server, or there is a proxy blocking WebSockets. If you have multiple servers check that sticky sessions are enabled.
Warning: Failed to connect via WebSockets, using the Long Polling fallback transport. This may be due to a VPN or proxy blocking the connection. To troubleshoot this, visit https://aka.ms/blazor-server-using-fallback-long-polling.
Here is the solution described again, maybe a little bit more convenient:
To fix this problem, I changed in the site-configuration (/etc/nginx/sites-available) of nginx the following variables:
proxy_set_header Connection $connection_upgrade;
to
proxy_set_header Connection $http_connection;
For me this solved the problem.