RT-IR-4.0.0 Installation Error (Fedora 27)

In Fedora 27, after a successful installation of RT 4.4.2 from the
repository, I install RT-IR 4.0.0 following README with no visible
installation errors.

After enabling plugin RT::IR in Siteconfig I get an apache 500.

Apache error log states “Can’t locate RT/IR.pm: /RT-IR/lib/RT/IR.pm:
Permission denied at /usr/share/perl5/vendor_perl/RT.pm line 757.”

I’ve granted rwx permissions for everyone to both /RT-IR/* and
/usr/share/perl5/vendor_perl/RT.pm, but the error persists.

Do you have any clues on how to fix this?

Thank you very much!