@supportadtribes Hello everything is fine? I contacted meta support and this was the response:
By checking the built-in tools, our expert team discovered that the reason you are getting an error when adding XML to your data feed is because there is no <?xml declaration tag at the beginning of the file.
Therefore, to resolve your situation, you must place the <?xml declaration tag at the beginning of the file, when you add the xml to the data feed (in the step shown in your printout).
For more information you can access the link below:
Reference – Catalog: https://developers.facebook.com/docs/marketing-api/catalog/reference/#da-commerce