If the app is in TEST mode, you will see a yellow banner at the top of the app saying Test Mode is enabled.
If the app is in TEST mode, you need to use the first name "Bambri" for the shipping address at checkout to see rates from the app.
If you don't have first name Bambri in the shipping address in Test mode, no rates from the app will show.
Make sure you spelled it correctly!
Learn more about testing rates in Test mode.