I worked with envato API for a year to check buyer purchase code to verify item purchase.
But the last 3 days, it’s always return 404 or purchase not exist, even I use various working & active purchase code. I use this Look up purchase by code
It looks like you might be using the wrong endpoint? The one you linked is /buyer/purchase – this is for buyers to verify their own purchase codes, it will not work for authors. Instead, authors need to use /author/sale to check a purchase code provided by one of their buyers.