When I put that same address into the media_player play_media service, via node red, nothing plays out of alexa. I know it can work. If i put in an actual address off an mp3 located on the internet, it works.
So why is it not pulling the local mp3?
I tried changing homeassistant.local to the local IP of my machine but i think the issue may be is I am using home assistant on a virtual box. So the IP is actually the IP of my windows machine that is hosting the virtualbox. Virtualbox is setup as a bridged adatper.
Its an interesting question, that unfortunately I don’t have an answer for, but after reading your experience, plus after reading the following thread:
I have an idea about this. Amazon/Alexa usually requires a https (port 443) and a real SSL certificate when accessing a resource (such as an MP3 file). So this may be the reason why you aren’t able to play audio files locally but can over the internet.
