First check power to the music player and amplifier. If both have power, this could mean your music player is not up to date or hasn't updated it's license or playlist for a while.
We advise contacting PlayNetwork directly for immediate support. PlayNetwork Customer Support is available 24x7
Via Telephone: +44 (0) 1622 663345
If you have an issue with the amplifier, please raise ticket via Pronett with IMT.