Alexa not recognizing new HA devices

I have been using HA cloud and the HA add-in for Alexa for about a year, and it has been working great. In the past, whenever I added a new device or script to HA, Alexa found it very quickly.

I recently added a new Zigbee device and a new Matter device, and Alexa does not recognize the new devices. I have tried telling Alexa to discover new devices, but that does not help. It sees the Matter device, but since HA is already controlling the device I can’t add it to Alexa with the QR code, and I don’t see any way to tell HA to add Alexa as a controller.

I can still turn devices on and off using Alexa, so the integration appears to be working, other than recognizing the new devices.

What do I need to do in order to get Alexa to recognize my new devices? Is there a problem with the HA-Alexa integration?

I discovered that in my settings for voice assistants, the Alexa assistant was not enabled to automatically expose new devices. Once I enabled that feature, the devices were exposed to Alexa, and are now working.