It got stuck at this step for quite a while:
Eventually it progressed (screenshot is here, I can only add one media item as I’m new member).
After that everything worked ok.
In the browser logs this is the 33 second delay, whilst connecting the websocket:
sip.js?v=1006:2900 Fri Sep 04 2020 17:53:13 GMT+0200 (Central European Summer Time) | sip.transport | connecting to WebSocket wss://ca.meet.coop/ws?sessionToken=lwx09foivtxjsu3w
sip.js?v=1006:2900 Fri Sep 04 2020 17:53:46 GMT+0200 (Central European Summer Time) | sip.transport | WebSocket wss://ca.meet.coop/ws?sessionToken=lwx09foivtxjsu3w connected
Here is the entire browser console log for that time.
Somebody else had reported the same symptoms earlier in the session (not much happening at the echo test stage, possible it would have connected had they waited, who knows…).