How can I successfully upload my data source to Pinterest Catalog?

I came across this problem too and tried adding .atom at the end of my shopify URL for the data source URL for Pinterest. It seemed to work at first except for the 25 error links that other people have mentioned. Then I tried to save the CSV from Shopify to my Dropbox, and use the URL from there, but that didn’t work. Then I looked for the a Pinterest-compatible app (I can’t use the Pinterest app because I’m based in the UK), and then saw some product feed apps like these https://apps.shopify.com/product-feeds-generator?surface_detail=pinterest&surface_inter_position=2&surface_intra_position=4&surface_type=search and one called GMC Feed that I downloaded, it then generated a URL that I copied into Pinterest and the link seems to have been accepted. Now I have to wait 24-48 hours to see if it actually worked. Either way, it looks like there are apps out there than can generate product feeds for you to just copy the link to wherever you want the feed.