If a Pinterest link will not download, start with the basics: make sure the link is to a public pin and not a private board, secret pin, or login-gated content. Private pins cannot be analyzed by any public tool.
Next, check that you copied the full link from Pinterest's Share menu. Shortened pin.it links work, but broken or malformed links will not. Try re-copying the link and pasting it again.
If the site shows an extraction error, the pin may not have an available media stream in the format you selected. Try a different format — for example, MP4 instead of MP3, or JPG instead of GIF — since not every pin has audio or every format.
On iPhone, if a downloaded video does not appear in Photos, open the Files app and use the Share sheet to save it to Photos. iOS limits which media types can go directly to the gallery.
If none of these steps work, contact support at contact@pinsaver4k.com.