keep on getting Missing grantUrl in setup function

[AlladinSa]

i have been following all the steps mentioned in the documentation of this code base as well as the official documentation including serving my app in ngrok..etc however; whenever i click on the connect to QBO button, i get this error from the console.log saying: Missing grantUrl in setup function in the file: https://appcenter.intuit.com/Content/IA/intuit.ipp.anywhere-1.3.3.js

Can someone please share with me what could the problem be in this case.