I use this demo local, chrome works well, firefox with this error log.
v3 branch latest code
firefox Version 70.0.1 (64-bit)
protoo-client:WebSocketTransport constructor() [url:wss://localhost:4443/?roomId=ziugvbj2&peerId=jnyo5kv1, options:undefined] +0ms common.js:121
protoo-client:WebSocketTransport _runWebSocket() [currentAttempt:1] +2ms common.js:121
protoo-client:Peer constructor() +0ms common.js:121
Firefox can’t establish a connection to the server at wss://localhost:4443/?roomId=ziugvbj2&peerId=jnyo5kv1. browser.js:25
protoo-client:ERROR:WebSocketTransport WebSocket “error” event +0ms common.js:121
protoo-client:WARN:WebSocketTransport WebSocket “close” event [wasClean:false, code:1015, reason:""] +0ms common.js:121
protoo-client:Peer emit “failed” [currentAttempt:1] +78ms