|This is a software development site, not Apple support.
Read the error message, and it's obvious that it has nothing to with software development, and everything to do with the configuration of your Apple iClod account which we can do nothign about, even if we wanted to.
A trivial google would have found you the official solution: If you can't back up to iCloud - Apple Support[^]
In future, please do at least basic research yourself and not waste your time or ours ... and post support questions on support sites!
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