Sonos tends not to work on many guest networks, they are often  designed to block communications between devices, like between your controller device and the speaker, preferring to leave open only a connection between the individual device and the internet. 

Set up the Sonos on the main network, and everything should be fine. 

Thank you , I will give this a try.  I have the same SSID  for both 2.4 and 5 networks.  Do I have to assign a unique name to the 2.4 network and force Sonos to connect to it?

Just a side note, not being able to connect to a guest network represents a bit of a security risk.  Is this something Sonos will be addressing.

Thanks again for the quick response. 

I would try it without changing the network names first.

What security risk would be caused the need to put devices that need to connect to eachother on a network that provides this feature?  

Hi there- my understanding of the guest vs the default wifi networks is the guest network cannot access the admin side of the router hence limiting exposure to your home network.   That's why using the guest network is preferred when installing wifi peripherals.

I could be wrong.

Yes, I think you are.

I own an Asus RT-AX58U router, when I am in guest mode I cannot access my router settings, hence I cannot access any of the home network options.   Here is a section I copied from the URL link provided.

“We’ve seen D-Link, Netgear, and ASUS routers provide proper guest networks in this way. They create a separate, encrypted Wi-Fi network and isolate it from the main network. The most important thing is that encryption is available.”

https://www.howtogeek.com/219808/warning-%E2%80%9Cguest-mode%E2%80%9D-on-many-wi-fi-routers-isn%E2%80%99t-secure/

For this reason it is best to connect to the guest network when connecting wifi devices, this should include Sonos equipment.

You misunderstand what the site is saying.  Bottom line, from people who actually know what they are talking about:  Sonos will not work on a guest network.  Period.

The safety of a guest network is that someone using it cannot get to your printer, NAS, or Sonos devices.

The link you posted is about the security of guest networks (for your guests using it), not about a guest network being safer than a normal network. I would not be to afraid about your Sonos devices accessing your router setting - they have security updates (too many according to some), so you do not have to worry about security. You do let your phone or your printer on your private network, don't you? In this link the difference between guest networks and private networks is explained: Lock Down Your Wi-Fi Network With Your Router’s Wireless Isolation Option (howtogeek.com). Wireless isolation is what's troubling your Sonos set up.

Anyway: Sonos won't work on a guest network, so if you do not trust Sonos on your private network, you cannot use Sonos..