Does bulk create pins by uploading csv really work? I tried so many time but failed.

I tried to bulk create pins using this link: https://www.pinterest.com/settings/bulk-create-pins/. It only worked three times. Most of the time, it reports a format error, even though I am using the same format. I tried lots of image hosting to test is url correct. Occasionally, it indicates a successful upload, but the pins are not created. I am tired of this thing.