By default PDF and images needs to be on the same server. To use resources from another domain you need to add Access-Control-Allow-Origin header to server response, for example to allow http://foo.example to load the resources you need to add header

Access-Control-Allow-Origin: http://foo.example

Please check your browser console for errors. In most cases the problem is that flipbook has no PDF/images specified, or is trying to load PDF/images from another domain. There might also be other javascript errors on the page, coming from another plugin. Try to disable other plugins to see if another plugin is causing the problem.

If you get error that looks like this

Mixed Content: The page at 'https://www....' was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint 'http://www....'. This request has been blocked; the content must be served over HTTPS.

that means that your page is serverd over HTTPS so you need to load resources over HTTPS also, so you need to update pdf url or page image urls and replace http:// with https://

1. Try setting lower resolution for flipbook pages on mobile, for example

Real3D Flipbook -> Settings -> Mobile -> PDF page  size -> 1500

2. Try using different view mode for mobile, for example

Real3D Flipbook -> Settings -> Mobile -> View mode -> 3d

Quick method with shortcode:

1. Add shortcode to post or page where you have your button or link

   [real3dflipbook id="1" mode="lightbox" class="book1" thumb=""]

2. Add CSS class “book1” to your button or image

Another method

1. Add custom CSS class for flipbook, for example

   Edit flipbook -> Lightbox -> CSS class -> book1

2. Set flipbook mode to “lightbox” with

   Edit flipbook -> General -> Mode -> lightbox

   and hide thumbnail with

   Edit flipbook -> Lightbox -> Hide thumbnail -> Enabled

3. Add flipbook shortcode to post or page where you have your button or link
4. Add CSS class “book1” to your button or image

1. Set custom deep linking prefix for flipbook, in Edit flipbook -> General -> Deep linking prefix, for example “book1_” and set flipbook mode to “lightbox”
2. embed flipbook in post or page
3. if your lightbox flipbook is at http://example.com you can open flipbook at page 1 with http://example.com#book1_1 or at page 3 with http://example.com#book1_3

Your PDF probably doesn’t have real links (annotations of type link) but only standard text. Such “links” can work in e.g. Adobe Reader, but only if you have enabled automatic creation of hyperlinks (this setting seems to default to on).

1. add your Google Analytics tracking ID in Settings -> General -> Google Analytics tracking ID, which can be found in your property settings
2. events that are sent from flipbook are “page change”, “lightbox open”, “download PDF”

Here are couple of ways to improve PDF flipbook loading time

1. check if you have “range requests” enabled on your server. Range requests are used for partial PDF download, so pages can be displayed without loading the entire PDF. To see if PDF partial download works open browser console, Network tab, and check if PDF file is requested once or multiple times

2. try to optimize PDF for web use

• Avoid using high resolution images—150 dpi resolution for scanned images shall be enough for screens, especially for low powered devices;
• Try to use JPEG encoding for color images/photos in RGB colorspace when possible;
• Avoid using expensive compositions/effects such as transitions/masking—flatten transparency;
• Avoid using PDF generators (or don’t create content) that produce ineffective PDF output (e.g. LibreOffice creates a lots of tiny images for vector elements/pictures it does not understand);
• If there is such a setting, use web-optimized PDF output / linearization;
• Fix or don’t produce corrupted PDFs that do not conform to the PDF32000 specification.

3. optimize PDF flipbook with PDF Tools for Real3D Flipbook Addon This addon exports PDF to images and JSON on the server so flipbook will load much faster but it will keep all PDF features (links, text search, text selection)