Play music App wont function ?

[testcurve]

Thanks for taking the time to read this and as a newbie I know its probably a easy one this but when I try to play music after pressing the play music app  I just get a message saying ' Music temporarily unavailable' 'Couldn't play the the stream you requested' and a Done button but no further info, I get exactly the same thing on my Nexus 4 and my laptop, any ideas lads and lasses ? Thanks. Peace.