Attached are a more detailed debugger traceback and the JSON with ebaysdk DEBUG= true for verbose API call check,.
On-line documentation states that the sellerName field is “conditionally” but does not explain what the conditions are.
https://developer.ebay.com/Devzone/finding/CallRef/findItemsByCategory.html#outputSelector
Attached is some debugger info using the ebaysdk version 1.13.0 at the point of failure. Note that the itemId is 202290400892 and if you search for it on the US eBay shopping site, it finds the item and it appears that the storeName and sellerName are the same from the item’s listing and Seller details pages.
Python raises a TypeError because it expects a str but gets a None.
The XML/JSON tags are there, just empty in between them. I use the EBAY-US as the siteid in the API request call yet this lot appears to originate from Hong Kong; could that be part of the issue?
Is MySQL the DB, and is the sellerName field NULLable?