Since they’re to be used as surrounds,  factory reset both of them, then add them back one at a time before switching them from the ‘new’ room to be surrounds.

I’d be tempted to reboot the router before doing this, though. 

Hi @Bheam05.

Welcome to the Sonos community and thanks for reaching out to us. I understand it can be quite frustrating when a simple procedure does not work let us help you with that.

I do agree with @Airgetlam’s recommendation. Once both devices have been factory reset. Add them first on the Sonos app as a new room one at a time until the setup is complete prior to adding the second device you’re going to use as surrounds. Open the Sonos app, Go to settings » systems » add product. When prompted to add another device during the set up of the first Sonos device, select not now and proceed until the setup is complete. Once both of the Sonos devices are added individually and are both showing on the Sonos App, then we can proceed on adding them as surrounds. 

I hope we were able to help.

Please let us know if you still have further questions or concerns. We are always here to help out.

Thanks,