do not send 502 on failed websocket, just send back ECONNRESET

packages/server/lib/server.coffee

@@ -644,22 +644,11 @@ class Server
         socket.end = ->
           socket.end = end
 
-          response = [
-            "HTTP/#{req.httpVersion} 502 #{statusCode.getText(502)}"
-            "X-Cypress-Proxy-Error-Message: #{err.message}"
-            "X-Cypress-Proxy-Error-Code: #{err.code}"
-          ].join("\r\n") + "\r\n\r\n"
-
-          proxiedUrl = "#{protocol}//#{hostname}:#{port}"
-
           debug(
-            "Got ERROR proxying websocket connection to url: '%s' received error: '%s' with code '%s'",
-            proxiedUrl,
-            err.toString()
-            err.code
+            "Got ERROR proxying websocket connection to url: received error %o", { err },
           )
 
-          socket.end(response)
+          socket.end()
 
       proxy.ws(req, socket, head, {
         secure: false

packages/server/test/integration/websockets_spec.coffee

@@ -59,7 +59,7 @@ describe "Web Sockets", ->
         expect(err.code).to.eq("ECONNRESET")
         done()
 
-    it "sends back 502 Bad Gateway when error upgrading", (done) ->
+    it "sends back ECONNRESET when error upgrading", (done) ->
       agent = new httpsAgent("http://localhost:#{cyPort}")
 
       @server._onDomainSet("http://localhost:#{otherPort}")
@@ -68,11 +68,9 @@ describe "Web Sockets", ->
         agent: agent
       })
 
-      client.on "unexpected-response", (req, res) ->
-        expect(res.statusCode).to.eq(502)
-        expect(res.statusMessage).to.eq("Bad Gateway")
-        expect(res.headers).to.have.property("x-cypress-proxy-error-message")
-        expect(res.headers).to.have.property("x-cypress-proxy-error-code")
+      client.on "error", (err) ->
+        expect(err.code).to.eq('ECONNRESET')
+        expect(err.message).to.eq('socket hang up')
 
         done()