Websocket connect err.","error":"websocket: the client is not using the websocket protocol: 'upgrade' token not found in 'Connection

Hello @amy.blais,
and thanks for your reply.
I read that page at least four times and tried all solutions proposed but no luck.
Tried to switched AlloCorsFrom many times with different values, also with ‘*’ but after a while error arise.
Tried also to change this line:

proxy_set_header Connection “”;

to

proxy_set_header Connection “upgrade”;

in the location / { bla bla directive , but does not help.

For sure the error comes from nginx cause it’s clearly stated in Google Chrome Developer console:

WebSocket connection to ‘wss://mm.website.com/api/v4/websocket’ failed: Error during WebSocket handshake: Unexpected response code: 400

Searching in the forum I noticed this problem has been alredy discussed various times (i.e. How to fix websocket error? - #11 by amy.blais ) but apparently without a “standard”
solution.

The only different thing from the documentation is the backend ip: I need to put 127.0.0.1 cause my virtual machine does not have an internal ip.

Thank you.