Locked notes is not opening it is saying to turn on icloud keychain and it is already on but still not working

Hi stranger273,

Thanks for posting in Apple Support Communities.

It sounds like you're unable to unlock your Notes due to this iCloud prompt. Go to Settings > your name > iCloud > Passwords and Keychain. Turn off Sync this iPhone and turn it back on.

If this behavior continues, contact Apple to check into this behavior.

Get Support

Regards.