The password is failed to login because special character symbol like “$”(dollar sign) is considered to be special character in Linux.
drush upwd USERNAME --password="PASSWORD"
This command is actually running for Linux in which some special characters always needs to be escaped with “\”. So if you try the password:
drush upwd root --password="S$1gma"
The above password will never work, to make the above password work you need to escape it...Read More