Hello All,
I encountered the same problem.
I have tried installing on local system, Ubuntu 20.04 Server, PHP 7.4.3, Ghostscript 9.50, everything works normally.
I got error "Cannot open the PDF. The file may be corrupt, or in an unsupported format." when running moodle 3.9.2 on Shared Hosting.
It's an old RHEL 4.8.5-39, and as a user i get a jailshell and chrootjail, so i can't do anything. :D
However, the "system path" have been configured with ghostscript's path and other components, it's a green tick.
I've also checked that ghostscript is installed, even though it's not the latest version (it is 9.25, current latest 9.53.1)
And System environtment on my Shared Hosting Moodle look like normal:
is there any other way to check the cause of this problem?
Thanks,
Fathur