Here is how I fixed this
1. Go to "Configure test events" from the drop down next to "Action" drop down of the skills you are in.
2. A new window "Configure test event" will open and choose "Create a new test event" radio button
3. From "Event template" drop down, select "Aelxa Start Session" (scroll down in that window)
4. A bunch of JSON shows up, substitute applicationId with real appid of your skill in couple of places in the above JSON file.
5. Give a name to this event and save.
6. Should take you back to the lambda function browser session and now click test with event created above in step 5.
This worked for me. Hope this helps others.