'Service mqtt.publish not found' when attempting to use AWS as MQTT broker

I am attempting to set up my Hassio so that it will communicate via MQTT with my AWS IoT server. I would like to use my AWS IoT server as the broker, and send data for my sensors to a DynamoDB table. I was attempting to follow this tutorial loosely to get this set up https://medium.com/@crhuber/monitoring-plants-with-aws-iot-and-home-assistant-e5aaae42a582. I have the following in my configuration.yaml file:

29%20AM

I am using an automation to send data via MQTT to my AWS server, but receive the following error:

Can anybody assist me in getting this error resolved? I can’t seem to get the mqtt.publish service loaded no matter what I try.

Thanks a bunch!!

SOLUTION: changed “certificate: “/ssl/certs/rootCS.pem”” to “certificate”: auto.