Firefox & tor browser flood the js console with "cannot connect to wss://…" before login and also after successful login into pleroma instance

Firefox message: «Firefox не может установить соединение с сервером [translation: cannot establish connection to the server] wss://social.cryptoanarchy.rocks/socket/websocket?token=undefined&vsn=2.0.0.»

torbrowser message is the same.

Before the login into pleroma instance (in a fresh anonymous session), several identical messages also appear at js console.