Accidentally lock rds master user, How to unlock it again?

Hi,

Please try to reset the rds master user password using the AWS console or aws cli command and then you should be able to login again with the new password.

Reference repost article to reset the master user password for RDS database - https://repost.aws/knowledge-center/reset-master-user-password-rds

Sample aws cli command to reset the master user password,

aws rds modify-db-instance --db-instance-identifier mysqldb01 --master-user-password "xxxxxxx" --region us-east-1