If you have forgotten your Server Manager password, you can reset it by following these steps:
config.yml file in a text editoradmin_password_override setting, and set it to have a password, e.g. admin_password_override: somepasswordadmin_password_override to be empty again, and finally start the Server Manager.From then on, you should be able to use the password you set in step 6.
If you have forgotten your server password, please follow these instructions to reset it.