I have a Alexa skill that I'm trying to get working well with the built-in Alexa PIN slot (4-digit numeric code). The skill does have a large number of intents. However, I would have thought Alexa would have no trouble recognizing 4 digits spoken by the user. Instead, the intent with the PIN slot almost never gets returned. Instead I almost always get one of the other intents that are built into the skill.
What can I do to get better results with the PIN slot?