I back up via Time Machine to a NAS. The backups stopped working as soon as I upgraded to Sonoma 14.0. I couldn’t manually start a backup either. I disconnected the backup drive in Time Machine Settings and when I tried selecting it again, it wouldn’t connect. Instead, the dialog window would freeze. I’ve tried it several times after force quitting the Settings and I also rebooted the Mac. Still the Time Machine backup drive couldn’t be connected. This connection occurs automatically via SMB. So, finally I mounted the same network share in Finder via AFP and then selected this network share in Time Machine settings as a backup drive. And the Time Machine backups started working. I’m sure there is an SMB bug in Sonoma 14.0.