Failure of setting of Fondy Payment system to my main domain of shopify store

[Oleg8]

Good day to all, I need help to make setting of Fandy Payment system to main doman of my store.

Kindly be advised that yestarday I have been accepted as merchant at the Fondly payment provider.

When Fondy provided instructions for instalation and link of plagin to verify with shopify store.

I have created two domains on my store first - oleg-291.myshopify.com - initial when created my store and  second main which is related to my brand - www.stunningyoubeautystore.com what is actualy related and seen by my customers. 

Problem is when I opened the link from payment provider I can see and choose the first domain oleg-291.myshopify.com only but I need to instal payment system plagin to my main domain www.stunningyoubeautystore.com which is related to customer payment for orders.

Appreciate you best assistance in this matter and suport from peaple may help me in this matter.

Thank you.