OK, I figured the solution to add Sirius. First, you must have ALL ACCESS which includes STREAMING (unless there is a plan for streaming only, perhaps). Second, you must have logged into a separate site for streaming Sirius, player.siriusxm.com
Third, you must have your username and pw for Sirius ready.
Fourth, open SONOS app, SETTINGS>SERVICES & VOICE>ADD A SERVICE>SIRIUS>then log into the fields your username & pw for Sirius. ENTER. That should do it.
It used to be simple add music, but now you must verify on the SONOS app that you are bonafide account for streaming with Sirius.
ONE MORE THING, you must delete the Sirius channels you previously added to My Sonos, then re-add the same and after the above ADD SERVICES & VOICE. That validates your channels under new control noted above (where you logged into Sirius on the Sonos app).