There is a continuing error with the PDF Display plugin in 3.3.x which I am unable to pinpoint because it happens on my production server but not on my testing server (to which I have full access).
Documented previously here although it was not resolved except by deactivating PDF.JS plugin: PDFs are not displayed after upgrading from 3.3.0-13 to 3.3.0-14 - #3 by Nicolae
Steps I took leading up to the issue
Articles uploaded in PDF format lead to a HTTP 500 error.
Articles uploaded in HTML format work fine, and when the PDF Display plugin is disabled the PDF download correctly, confirming this is not a file directory error.
Perhaps worth noting is that Chrome and Edge display a file safety warning (“This file can’t be downloaded securely”) when downloading.
Firefox on the other hand does not display this error (and also doesn’t display a HTTP 500 error when the plugin is disabled, but a blank page)
I have also tried updating PDF.JS to the latest version available on their website both legacy and regular version, which did not alter the results.
What application are you using?
Currently using OJS 3.3.0.14 although I’ve tried up to 3.3.0.17 and the issue persists