SignalR: Error during WebSocket handshake: Unexpected response code: 400

Question

I have just started working with SignalR. I have implemented real-time data reflection on my site using signalr. I was getting "Error during Web-Socket handshake: Unexpected response code: 400" error on console with when trying to connect with web-socket.

Application is developed with Asp.net MVC - signalR 2.0.3 and hosted On Windows server 2012 - IIS 8

I found one solution from this link

It says that We need website to point to HTTPS (and avail SSL) then http to work with web-socket. And my Issue resolved too. My doubt is - cant we solve this issue without using HTTPS ? As each website might not require to be hosted on HTTPS (which requires SSL).

Your website may be served through HTTP while your WebSocket connects over SSL(WSS). This is a normal/working scheme... — Malkocoglu, Apr 17 '14 at 10:16
My request points to ws://* only and not wss://* which displyed in console error — Roshni Shah, Apr 17 '14 at 10:47
Well, I do not know how SignalR functions but I know it is possible to server HTML over HTTP and websocket over SSL... — Malkocoglu, Apr 17 '14 at 10:56

score 35 · Answer 1 · answered Dec 19 '15 at 09:59

35

use this tag in your web.config file :

<httpRuntime maxRequestLength="40960" targetFramework="4.5" requestValidationMode="2.0" />

under <system.web> tag. Describe your target framework.Error will be disappear

answered Dec 19 '15 at 09:59

Saurabh Srivastava

1,093
14
27

11

@DanielMinnaar, Sure! Because Microsoft. – Oleg Grishko May 03 '17 at 11:02

score 5 · Answer 2 · answered Apr 17 '14 at 10:12

If the problem are the proxies that exists in the path from client to server, there is nothing you can do but complain to your provider (both client and server).

How HTML5 Web Sockets Interact With Proxy Servers

By using a secure connection, you ensure that no proxy is going to mess with your connection.

score 5 · Answer 3 · answered Apr 08 '20 at 07:20

5

I was having same issue in .Net Core Web API with Angular 8 front end. The issue in my case was the Websocket protocol was not installed on server. Installed it from Server manager -> Add Roles and Features and it worked

answered Apr 08 '20 at 07:20

Shahid Iqbal

375
3
5

This also works for me. Ionic + .Net Core + SignalR application – Miguel Carrillo Jun 12 '20 at 22:55
This also works for me. Vue + .Net Core + SignalR application – Andy Wijaya Jan 28 '23 at 17:39

score 2 · Answer 4 · answered Nov 15 '17 at 15:54

This 400 error can also happen if you are running on multiple servers behind a load balancer. Inspect the body of the 400 response (ex., using Fiddler) and see if you find this: The ConnectionId is in the incorrect format. If so, then your problem may be that you are not using the same machine key on each application server.

See this answer for details on the solution: https://stackoverflow.com/a/43479474/979202

score 0 · Answer 5 · answered Oct 09 '19 at 00:26

If you're behind Nginx, add these three lines (the ones starting with proxy_):

server {       
    listen       443; # Or 80 or whatever
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    ...
}

HTTPS/HTTP is not the issue. WSS will be automatically used on HTTPS pages, and WS used on HTTP, without any manual setting.

SignalR: Error during WebSocket handshake: Unexpected response code: 400

5 Answers5

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