How to resolve OAuth authentication issues for my app integration?

[sap101094]

Hello all,

I am integration shopify in my application and I am implementing oauth authentication with the same.

1. I have created Partner's account and then created one app inside that account. 
2. I have created one development store
3. I did not register for shopify app store for app listing with 99$.
4. I have added api key and api secret in my app as well but whenever I try to give access of merchant account to partner's account by signing in merchant account in dialog prompt then it gives me a below screen in popup.
   
   
   
   Can anyone help me on this? Does anyone has any idea on this? Please help me as I am blocked.