Time Machine says can't backup because "running on battery power", but it's plugged in.
I have restarted my MacBook Pro. Tried skipping the back up and starting a new one. Nothing works. Running Sonoma 14.1.2
MacBook Pro 13″, macOS 14.1
Does the icon in your top menu bar indicate your Mac is plugged in? If it is, it should show a plug overlaid over the battery icon. If it's not, then your Mac isn't getting any power from your charger.