its LIKELY A CHANGE IN YOUR WIFI network, causing a dropout. I’d review the the wifi interference FAQ, particularly with regards to outside influences, which often are the source of issues. 

If my other music streaming services dropped out I could see it being my WiFi but SiriusXm is the only one that does it.

That would certainly suggest an issue at SiriusXM, rather than at your end (or Sonos, for that matter). If it was an issue with Sonos, it would affect all streams equally, not just SiriusXM. Since 

The challenge is you say its “minutes to hours”, which still suggests wifi interference, particularly from outside your network. Like when i had new neighbors, and their new router sat on the same channel that I happened to be using for SonosNet. Not something I controlled, but a change in the environment for my Sonos system. 

Our wifi networks do not sit in isolation. They’re affected by all sorts of outside influences. 

I am having the same issue at a clients location.  Worked fine for 1-½ years.  Wired network connection.  Tune in plays fine.  Sirius drop out times range from minutes to hours.

sirius says they do not have an issue.

sonos blames the network that has not changed.

looking for a new solution for future commercial projects.

I had and continue  to have the exact same problem, and I know it is not my wifi . Wifi has been completely  upgraded to a mesh network and the problem has persisted with the Play 1 speakers. No other devices( Roku, firesticks, Chrome cast, Win 10 and Mac laptops, alexa, Nintendo switch)  on my home network have any issues. BTW- I do IT for a living. 

If I play Sirius XM via their app on my phone to a Chromecast audio, there are  no problems . And it will play without fail. 

i have submitted diagnostics in the past and the same ridiculous comments come back about issues with the wifi. 

Having owned these speakers for 3+ years, installed all of the upgrades and  had this problem for just as long, I would never buy a Sonos product again. They  are unable to  troubleshoot  their own proprietary  product. 

Hey all - have been experiencing this recently and took to Apple TV to play and then extend Sirius across the speaker network. About 30 seconds in I got a message saying that “more than on device is using this account”. I think that's the issue. It's not a bandwidth problem, it's the fact that other devices are logged in to the account and it's cutting off the Sonos player. 
 

Will investigate further but wanted to let you all know. 

Same issue.  Only SiriusXM randomly drops out.  All other streaming services are fine.  The problem started a day or two ago (12/08/23).