API Integration error

[NickPinocci]

Hey all! 

We have partnered with a gift card company that sells our gift card's on their website and all orders are processed through our shop. When we try to integrate using a generated API key (with full access). We just get this error:

POST https://2bb7cc731096fb5319e8ed2ca02a45d4:***@SHOPNAME.myshopify.com/admin/api/2021-07/gift_cards.json` resulted in a `404 Not Found`

They have other Shopify stores and we have other API's working on our site currently (Attentive, Royal Mail + DHL). Is this a common issue and any help would be greatly appreciated. 

Thanks 

Nick!