Websocket handshake failing (1 reply)

I'm trying to enable websocket communication between client and server and have nginx as proxy. Ive applied the following congiguration changes to websocket sites-enabled conf to allow for websocket proxy:
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header X-Forwarded-For $http_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_pass http://mywebsite;

Although the server receives the Connection: Upgrade header and responds with aConnection: Upgrade header as expected, the client gets only Connection: keep-alive and I see the following error on js-console

WebSocket connection to 'wss://mywebsite.dev/cometd/' failed: Error during WebSocket handshake: 'Connection' header value must contain 'Upgrade'

I feel that nginx might not be proxying the response correctly either due to incorrect response or bad config.

Can someone help me out with debugging this? A lot of places where I see this issue, usually the proxy does not support the websocket handshake which causes the handshake to fail.

Appreciate the help!