Why do my Alexa notifications no longer work?

I have a few automations which include an Alexa notification. They used to work but no longer do. I have not changed my Amazon Dot, so assume it’s something that has changed in Home Assistant?

service: notify.alexa_media_mr_s_echo_dot
data:
  message: Night night
  data:
    type: tts
    target:
      - notify.alexa_media_mr_s_echo_dot