I'm trying to use the Skill Messaging API to send an out-of-session message to my Alexa skill in development. I'm able to get an access token and I receive a 202 Accepted response back from the API, but the message is never received by my skill. I have a RequestInterceptor that logs all requests to the skill and I have a RequestHandler for Messaging.MessageReceived requests.
I'm confident that it's not an issue with my post request to the API since I still get a 403 Forbidden if I intentionally use an invalid access token and a 400 Bad Request if I send a request with invalid message data.
If it makes a difference, my skill is considered a healthcare skill as well.