Till now it worked trouble-free but suddenly playTrack stopped playing my MP3 files.
Everytime I try it now - no matter whether manually or via Rule Machine - there comes at max the Google "beep" (Chromecast device wakes up), and than I find this error in the log: su.litvak.chromecast.api.v2.ChromeCastException: Unable to load media (playTrack)
I can reproduce this error on any of my Chromecast device.
Apart from some recent Hubitat updates nothing has changed; The MP3 file on my local web server (access via http) is reachable, casting from smartphone is working, device discovery reruned, ...
BTW: Device commands like speak are still working.
The file is case sensitive. I just entered http://hubip/local/TheImperialMarch.mp3 in the Play Track Field on my Google home and verified it works as expected.
OK I've found a workaround: playTrack works, when I use the IP address of my local webserver instead of the DNS Name.
@support:
Dear Hubitat team, please never change again such important settings like Networking (or at least ask for permission); You have cut my local DNS server for no reason!