I don’t think you can. Sonos app has some kind of song queue limit with some (all?) music services. It’s like it doesn’t load all the songs, at least that’s my experience. 

Thanks for your response.  It certainly appears that way.

 
I have an older speaker that does not support airplay so it appears that I am stuck unless I manually create a 1200 song Sonos playlist one song at a time (a ridiculous alternative)

I think I may have abandon Sonos.  Great speaker but their app and features are way too buggy and limited 

Try the Desktop app or third party. The mobile app does have some weird size restrictions.

Sonos recommend no more than 500 items in a container (a playlist is a ‘container’), but the actual limit is the 10 second timeout to load it.