Have the same problem, I think. I have HiFiBerry + on RPi2 Max2Play and – SqueezePlay player on Win10 which plays the TTS but none of the Squeezelite on Max2play installs are playing the TTS from the URL sent. I downloaded the file in LMS music folder and it plays fine on squeezelite/max2play- so is NOT as I saw on some forums a too short mp3 file or sampling rate not supported. Some are saying something about https – cannot find it right now – Any suggestions? – I did look on a lot of posts but so far no luck.