Rejecting secure audio stream without encription details

I’m trying jssip at tryit.jssip.net/

I’m using ws [NOT wss], so I’m expecting a non-secure connection, right?

I can register peer, no problem.
When I make a call, I get

Is there something wrong in the client or in asterisk ? It’s self-compiled from source [v 11.3.0 on a Debian 6]

The device offering the stream (might be client or server) is probably a little errant, but this doesn’t matter if there is an acceptable audio stream available, as well.