Cannot receive MQTT message

I've setup a simple test case with publish and receive steps. With various public test servers/brokers and a local Mosquitto server/broker. The publish step succeeds but the receive step fails every time. Another MQTT-Spy client subscribed to the same topic does receive the message published from SoapUI without error.

SoapUI 5.5.0 build date 20190211-1036

ready-mqtt-plugin-dist.jar dated 2/11/2019 12:41