My morning alarm has become increasing unreliable. I have a Sonos One in my bedroom. Recently, I was getting chimes more often than the music I had set up. I tried all the basics before resorting to a total rebuild. I have 14 Sonos speakers - the oldest are a pair of play:3 from 2013. I unplugged everyone. I unplugged my router and range extenders. I factory reset every speaker. Factory reset the router and range extenders. Set up the router and range extenders making sure latest firmware and keeping most default settings. Once I was happy wifi was working, I created a new Sonos account and added every speaker. All good. That was a week ago. Since then my daily wake up alarm has worked once.
I have Spotify family plan and we have an unused account which is only used by Sonos for alarms. When I play directly from Spotify App the music plays. When I pick the Spotify service in the Sonos App, it plays. When I create an alarm one minute in the future and test, it works.
Sonos One
Hardware Version : 1.21.1.8-2.2
Software Version : 85.0-64200
Sonos iOS App Version : 80.21.6
Spotify iOS App Version : 9.0.48.415
Router TP-Link Archer AXE75 + RE550 / AC1900 Wi-Fi Range Extender
Networks : 2.4GHz + 5GHz
Happy to provide any additional information to resolve this issue.