[App][Pro] Micro Web Server

I am trying to play a small mp3 file on a google home speaker, but i am not able to.

the server is running, i am copying the http://homey-5xxxxxxxx2e7186:5080 line and adds /Santa.mp3

when i run test on the phone app the google speaker makes a pling sound, but when i test on flow site on computer i get " Flow card error: Proimise was rejected with falsy value".

any ideas?