ERPNext with Shopify integration issue


I am facing one issue with shopify to erpnext connection. Our ERPnext setup is cloud based. Please help me for connecting our shopify system and ERP System.

Below are links of ERPNext and shopify.

Shopify link :-
ERPNext Link :-

We have installed ERPNext public app in shopify admin and when we clicked on that and give below inputs in field.

Shop Name:
ERPNext Site Name:
ERPNext User Id:
Password: #####

When we clicked on submit button it gives " 504 Gateway Timeout error is an HTTP status code".

We have ERP latest version on cloud server.

is your issue resolved? are you facing any limitations with shopify integration?