Error when exporting Print PDF

We have a faculty member who is getting the following error message when exporting. All other exports work fine, it seems to just be the Print PDF that fails:

[site_url] => https://pressbooks.bccampus.ca/meijiat150
[blog_id] => 445
[theme] => Open Textbooks
[url] => https://pressbooks.bccampus.ca/meijiat150/format/xhtml?timestamp=1553719883&hashkey=82ad49fca250b91a4292c94c74782718&pb-latex-zoom=3&optimize-for-print=1
)
Wed Mar 27 13:51:25 2019: ---- begin
Wed Mar 27 13:52:04 2019: https://pressbooks.bccampus.ca/meijiat150/format/xhtml?timestamp=1553719883&hashkey=82ad49fca250b91a4292c94c74782718&pb-latex-zoom=3&optimize-for-print=1: error: The requested URL returned error: 500 Internal Server Error
Wed Mar 27 13:52:04 2019: https://pressbooks.bccampus.ca/meijiat150/format/xhtml?timestamp=1553719883&hashkey=82ad49fca250b91a4292c94c74782718&pb-latex-zoom=3&optimize-for-print=1: error: could not load input file
Wed Mar 27 13:52:04 2019: error: failed to load all input documents
Wed Mar 27 13:52:04 2019: finished: failure
Wed Mar 27 13:52:04 2019: ---- end

Any advice on how to troubleshoot this issue?

This means something broke on the server.

Someone has access to the logs on https://pressbooks.bccampus.ca (Apache, PHP) find them and ask for those logs.

Another reason you’ll see an Error 500 is if the timestamp on the “temporary secret” url expired. For example if I click on:

https://pressbooks.bccampus.ca/meijiat150/format/xhtml?timestamp=1553719883&hashkey=82ad49fca250b91a4292c94c74782718&pb-latex-zoom=3&optimize-for-print=1

I’ll get:

This is because I’m an anonymous user. I’m not logged into BCcampus as an admin.

The URL above has several parameters. The timestamp combined with hashkey allows a 3rd party service temporary access to the XHTML file. Like DocRaptor, or Prince.

Make sure the URL hasn’t expired.