Hi @SANG_SIPIR,
You may want to try what is suggested here: Cannot view PDF file - #3 by azmi384
Also, in your posts, please include your OJS version number (e.g. 3.3.0-8), as this assists with others that may help you troubleshoot to identify appropriate solutions.
-Roger
PKP Team
hi @rcgillis
my ojs version is 3.2.1.4
I have read the issue, but I am still confused to change the url to https, what configuration file should I change so that the pdf file and the viewer are both https?
