Same thing here - I think the issue started when I created new alarms using the old Sonos app on an outdated iPad while I was simultaneously controlling my Sonos system from a recent iPhone running the latest Sonos app. I tried factory resetting some of my Sonos speakers but to no avail. My wireless network is reliable and is used for most of my Sonos speakers, with the exception of the Beam that has a wired Ethernet connection. I will try factory resetting the Beam just for the sake of being thorough but I am really out of ideas to get the freaking alarms working as they used to for the last years. The pivotal element is of course the new Sonos app that was released some months ago. 

same here. none work and I have uninstalled and reinstalled alarm setting, app and reset everything checked time zone….nothing. They stopped with new app update (total mess) but then with several updates after it worked for awhile but now nothing.