WebSocket error

I’'m creating an app to connect to the streaming WebSocket.
It appears that the connection work ok but right after connecting when I try to send the authenticate action as a JSON data I get the following
encountered error(1:57)

If I try too end a basic string “hello” I get the following error
missing error, so heuristics synthesized error(1:53)

Could you clarify to me what that could mean?

Thanks

Hi, what language are you using? (python, js, …)

This is for an app written in Swift.
Swift now supports natively WebSockets. I have no problem connecting to the socket, I get the acknowledgement of that. Thank when I try to send the authentication this is the answer I get.