Music on hold (MOH) allows you to select which file to use for MOH. Only wav and sln file formats are available for MOH. You can have several files identified for MOH, we have provided a default selection for you.

You can also use a streaming server to provide MOH, but beware, free services usually don’t like the constant 24h/day bandwidth usage, so they change often their link or block abusers.

Just as a proof of concept, you can connect to https://www.internet-radio.com/stations/ pick up your preferred station and download the .m3u file. Open the .m3u file with a text editor and use that link in Music On Hold page.
http://us1.internet-radio.com:8180/