Iphone backup failed notification

Hello and welcome to Apple Support Communities, dimitriy00!

We understand you're having trouble backing up your iPhone. We'd be happy to provide information to help you address this.

Try the steps outlined here: If you can't back up your iOS or iPadOS device to a computer or restore it from a backup

Have a great day!

Hello and welcome to Apple Support Communities, dimitriy00!

We understand you're having trouble backing up your iPhone. We'd be happy to provide information to help you address this.

Try the steps outlined here: If you can't back up your iOS or iPadOS device to a computer or restore it from a backup

Have a great day!

Hey dimitriy00!

That warning would appear if the backup failed with iCloud. Go to Settings > ["your name"] > iCloud and turn off iCloud backup.

Regards.