We typically advise customers against creating PDFs but some still insist on having this ability so this article has a few troubleshooting tips for those customers. PDFs are generated by converting HTML to PDFs using a program called Prince.
PagePrinceExportErrorFatalExceptionis generally indicative of a timeout error. This is most likely caused due to a large amount of content on the page. I would recommend splitting this content into smaller pages in order to have the ability to download the content as a PDF or hiding the export button using CSS.
Another way to export the page is by using your browser's Print functionality to create the PDF of the page. To clarify, the browser's Print option is not a MindTouch function and is therefore not brandable through CSS on the MindTouch platform.