How does Sonos connect to Apple Itunes?

I have been unable to update the sonos app as sonos can't connect to itunes.

A few bars of music are played and then it stops. When I try to update error message 30 and/or 1101 come up.

I have tried to follow the online instructions to correct but unable to get it to work. Up until 3 weeks ago I could play music all day. What would make the error occur?