Why Isn't My Split PDF Working?

There are two common causes. First, the file itself: if your PDF can't be opened at all — for example, if it's corrupted or password-protected — you'll see a "Failed to load PDF" error as soon as you upload it. Second, the page ranges: if you enter page numbers that don't exist in your document (for example, "1-20" for a 10-page file), those out-of-range pages are simply skipped rather than causing an error, so double-check the page count shown after upload and make sure your ranges fall within it.