Bertrand Guiheneuf

Hello @NghiaTranUIT I do confirm I'm able to reproduce the issue with swift-nio sample websocket server. https://github.com/apple/swift-nio/tree/main/Sources/NIOWebSocketServer At least now we can both investigate the issue :)

Ok, I've found the issue. It's due to the websocket server not returning the "elected" subprotocol in the response. In swift-nio sample, I replaced the [upgrader](https://github.com/apple/swift-nio/blob/main/Sources/NIOWebSocketServer/main.swift#L203) code : ```swift let...

Yes it works perfectly !!! Many many thanks 😃 😃