Shopify and ERPnext integration Error

Hello guys,

I have been trying to integrate ERPnext with shopify.
I totally understand that there is only one way of syncing which is from the shopify to the ERPnext.
After setting up everything i found in the shopify logs couple of logs shows error which puzzled me without any clue on where to go next.

First : Which API i am supposed to choose from Shopify if i have ERPNext: v12.12.1
Second : below is the error messages i am getting

First it gets queued to prepare for a sales invoice
43%20AM

Then it goes into error

04%20AM
14%20AM

While when the item is being fulfilled in shopify , i can see the log status as sucess but i dont know where did it go inside the ERPnext

48%20AM

Any help would be really appreciated, the target is whenever an item is being sold from shopify i want the process to initiate from ERPnext as if the customer bought it from our shop