Hi Logan, this is Ryan - I emailed you a link which demonstrates the issue with minimal code (and the code can be viewed by inspecting the page).
As of just a few moments I have updated the link so if you have taken a look at it between receiving the email and now, please disregard what you saw earlier.
What you will see when going to the link now is that PDF JS Express loads a PDF that our customer uses as a template. This PDF is fresh from Acrobat, never run through PDF Express JS before. Once PDF JS Express loads up, press the Save button at the bottom. A new Blob will be generated using the PDF JS Express API, and if successful, PDF JS Express will close and the new Blob will be loaded into a new PDF JS Express instance. Repeat the process. Each time the new Blob is loaded, press Save again, and after 2-3 iterations you will notice that it stops working due to the 504 error.
Thanks for taking a look
- Ryan