It could be mainly for two reasons:
The "reset your password" email was sent to your spam or junk folder.
The email address you entered does not exist due to:
A typo or misspelling
Attempting to log in to the Hilo App using credentials for the Hilo website (which is used only for orders). These two accounts are independent, and the Hilo app will not recognize your website credentials. Ensure you select "I have an account already" rather than "Get started".