Hi,
Received the below mail even though we did not done any changes in the account.. later we could login successfully with the old password.
Dear XXXX,
The password for your Apple ID has been successfully reset.
If you did not make this change or you believe an unauthorised person has accessed your account, go to iforgot.apple.com to reset your password without delay. Following this, sign into your Apple ID account page at https://appleid.apple.com to review and update your security settings.
If you need additional help, please contact Apple support