The information displayed by the browser is ‘An internal RT error has occurred. Your administrator can find more details in RT’s log files.’
I found the following error message in /etc/httpd/logs/error_log
[/usr/local/share/perl5/HTML/Mason/Interp.pm:348]
[/usr/local/share/perl5/HTML/Mason/Interp.pm:342]
[/usr/local/share/perl5/HTML/Mason/PSGIHandler.pm:59]
[/usr/local/share/perl5/HTML/Mason/PSGIHandler/Streamy.pm:52]
[/usr/local/share/perl5/Plack/Util.pm:339]
[/usr/local/share/perl5/Plack/Handler/FCGI.pm:149]
[/usr/local/share/perl5/Plack/Loader.pm:84]
[/usr/local/share/perl5/Plack/Runner.pm:277]
[/opt/rt4/sbin/…/lib/RT/PlackRunner.pm:150]
[/opt/rt4/sbin/rt-server.fcgi:162] (/opt/rt4/sbin/…/lib/RT/Interface/Web/Handler.pm:208)
[8729] [Mon Jun 4 06:03:53 2018] [error]: Couldn’t create object file /opt/rt4/var/mason_data/obj/3595297236/standard/dhandler.obj: Permission denied
Stack:
[/usr/local/share/perl5/HTML/Mason/Interp.pm:437]
[/usr/local/share/perl5/HTML/Mason/Interp.pm:773]
[/usr/local/share/perl5/HTML/Mason/Request.pm:256]
[/usr/local/share/perl5/HTML/Mason/Request.pm:212]
[/opt/rt4/sbin/…/lib/RT/Interface/Web/Request.pm:67]
[/usr/local/share/perl5/Class/Container.pm:275]
[/usr/local/share/perl5/Class/Container.pm:353]
[/usr/local/share/perl5/HTML/Mason/Interp.pm:348]
[/usr/local/share/perl5/HTML/Mason/Interp.pm:342]
[/usr/local/share/perl5/HTML/Mason/PSGIHandler.pm:59]
[/usr/local/share/perl5/HTML/Mason/PSGIHandler/Streamy.pm:52]
[/usr/local/share/perl5/Plack/Util.pm:339]
[/usr/local/share/perl5/Plack/Handler/FCGI.pm:149]
[/usr/local/share/perl5/Plack/Loader.pm:84]
[/usr/local/share/perl5/Plack/Runner.pm:277]
[/opt/rt4/sbin/…/lib/RT/PlackRunner.pm:150]
[/opt/rt4/sbin/rt-server.fcgi:162] (/opt/rt4/sbin/…/lib/RT/Interface/Web/Handler.pm:208)