When a document is uploaded to Dext as a PDF, it displays using your browser's built-in PDF viewer. If your browser is set to download PDFs instead of opening them, the document won't display in Dext.
Google Chrome
In Chrome, go to Settings → Privacy and security → Site settings → Additional content settings → PDF documents and select Open PDFs in Chrome.
You can also go directly to chrome://settings/content/pdfDocuments in your address bar.
Microsoft Edge
In Edge, go to Settings → Cookies and site permissions → PDF documents and make sure Always download PDF files is turned off.
You can also go directly to edge://settings/content/pdfDocuments in your address bar.
Mozilla Firefox
In Firefox, go to Settings → General → scroll to Files and Applications → find Portable Document Format (PDF) in the Applications list and set it to Open in Firefox.
Safari
Safari opens PDFs in the browser by default. If PDFs aren't displaying in Dext, check that you haven't changed this behaviour in Safari → Settings → General → File download location.