Did you try this?
And take a look at this vid please (it’s aimed at Home Assistant, but the only difference is entering the data in to the Homey app):
No, it’s not that. The IoT core is already a free trial when you started this.
Make sure to add a reminder every 6 months, to extend the IoT core trial period. In this topic several “how to extend it” 's, were posted.
