You can reset the password for the Plesk admin user by following the steps below:
- Log in to your server via SSH using the root username.
- Enter the command below, replacing ***** with the new password while keeping '' at the beginning and at the end:
plesk bin admin --set-admin-password -passwd '*****'
You will find in this article some tips for choosing strong passwords and thus protect your accounts: How to choose a strong password?