GrassBlade LRS currently do not have an interface for Forgot password.
If you are able to access the LRS from WordPress backend, you can login from there and change the password.
You can change the password from database. If you have phpMyAdmin it should be easy.
You can go to the table: wp_gb_users
And change the password to this string:
Your password will become: admin
Now you can login and change it again.