Media player configuration issues

I have a few google home devices configured in my house and I can issue messages to them like below, which works fine.

service: tts.speak
data:
  cache: true
  media_player_entity_id: media_player.family_room_display
  message: Cloakroom light turned on.
target:
  entity_id: tts.google_en_com

I have now configured the HACS skill Alexa media player, but the same message as before gives an error in home assistant as below.

Failed to call service tts.speak. Unknown error

A few times, Alexa did speak, but says it can’t launch the simon says skill.

If I issue the same message as below, it works fine on the echo.

service: notify.alexa_media_kitchen_echo
data:
  message: Test message 123

Am I doing something wrong here or is this the expected behaviour?