Sound Waveform R7ERR_FAILED

[andyarcimedia]

The rest service http://rest7.com/sound_waveform is not working for any URL, even with an API key entered.

Here's my request: http://api.rest7.com/v1/sound_waveform.php?url=https://www.akmmusic.co.uk/music/album_overviews/webpreviewAK236fun.mp3

The respnse: { "success": 0, "error": "R7ERR_FAILED" }

It's the same error if I try mp3 files from other websites. This worked fine a month ago, so not sure how to make it work?