Wrong Computer Name
I renamed the computer and Sonos would say it couldn’t find the old computer name. It wasn’t recognising or seeing the new name. I reinstalled etc. Then realised that there were a few issues. Firstly there were different queues for different speaker systems, these had been populated prior to the name change. I ungrouped the system and cleared each queue. Additionally, the queue that was in the main play area had been populated prior to the computer name change. I cleared all queues, updated the music library and voila!
