Most PDF FirstLook problems come from the PDF URL, same-domain restrictions, preview rendering settings, or a control that has been hidden. Test the published page before changing several settings at once.
The preview is blank or shows the fallback
Open the PDF URL directly in a private browser window.
Confirm that the PDF and the page use the same domain.
Make sure the file is a valid PDF and does not require a login.
Check that a CMS, Feeds, or macro-generated URL resolves to the final PDF file.
Test with a small manual PDF link to separate a source problem from a rendering problem.
The preview shows an older PDF
PDF FirstLook uses caching while ensuring changed files can be refreshed. Publish the current PDF and page, then reload the public page without an old browser cache. Confirm that the server is actually serving the replacement file at the configured URL.
A change to Preview Height or Quality rebuilds the generated preview. Use this only when the render settings need to change; it is not a substitute for publishing the correct PDF.
The wrong page is displayed
Check that the configured page number exists in the PDF. For multi-page mode, verify the initial page, Book or Single layout, and the options that return the document to its first page after the last page or after closing the lightbox.
Navigation or the control bar is missing
Enable Page Flip for multi-page navigation.
Enable Show Control Bar when visible controls are required.
Select the Prev/Next, Count, Jump, First, and action elements that should appear.
Check the control-bar position and offset.
Verify that control colors contrast with the preview.
Update to the current PDF FirstLook version when using multiple instances, Feeds, 3D page turns, rapid flipping, or keyboard control.
The action button does not work
Enable Show Button, choose Download, Show, or External, and verify the associated PDF or destination URL. Use a text label while testing so the intended action is clear.
The page loads slowly
Reduce Preview Height or Quality gradually.
Optimize the PDF and remove unnecessarily large embedded images.
Test a shorter PDF to determine whether the document size is the limiting factor.
Avoid rendering many large PDF previews above the fold on one page.
Keep lazy loading enabled through the normal stack behavior.
Accessibility checklist
Write meaningful ALT text for every preview.
Use descriptive labels such as “Download course outline PDF.”
Keep keyboard navigation enabled and verify visible focus.
Maintain strong contrast for the control bar and action buttons.
Do not make the preview image the only way to reach important document content.
Provide the document title, file type, and purpose in nearby page text.
Contact support
If the problem remains, email support@stackswork.com. Include the PDF FirstLook version, public page URL, PDF URL, browser and device, source type, and screenshots of the Document, Layout & Flip, and Preview settings. Do not send private documents or login credentials.
For the recommended setup sequence, see Getting started with PDF FirstLook.