Hello,
I’m trying to view my app, but it asks me to login, but when I enter my email, and password it told me it’s wrong even though I clicked forgot password, and entered my email they didn’t send me anything.
The email address could be different to that setup on the Knack Account object. 
Possibly why you can’t sign in and / or not receiving a password reset to the email address. If you are using the correct password and don’t have access to the builder then contact your app developer who can reset your password in the Accounts object.
I presume you are logging into the app URL and not the builder, which is a common mistake. If your login page looks like the below, that’s the Knack builder.
