Fixing an out-of-storage problem for iCloud backups

My mother-in-law's phone balked at backing up. But she has nearly nothing on it. The trouble? An accidental video.
icloud icon 2015
Apple
    Related:
  • Cloud Computing
  • Photography
  • iCloud
  • iCloud Drive
  • iCloud Photo Library
Glenn Fleishman’s most recent books include Take Control of iOS & iPadOS Privacy and Security, Second Edition (covering iOS 15/iPadOS 15), Take Control of Your M-Series Mac, and Take Control of Securing Your Mac. In his spare time, he makes Tiny Type Museums. He’s a senior contributor to Macworld, where he writes Mac 911.