I just started out testing thingstud.io and tried to connect to iot.eclipse.org but it does not connect. The websocket port is 80. I have no problem subscribing to my topics using MQTT.fx. Any special settings required to get it to connect?
edit: same thing with test.mosquitto.org
I also tried it through broker.hivemq.com (websocket port 8000) which kind of works but the subscription disconnects after 30 seconds or so for a brief interval and the data stream stops after the app reconnects.