Restarting apache temporarily resolves.
Also, the following repeatedly appears in /var/log/httpd/error_log:
Argument "-" isn't numeric in numeric gt (>) at /usr/sbin/vlogger line 456, <STDIN> line 18
I tried this:
but no real difference, same error shows up in the error_log
perl-TimeDate is installed
which vlogger outputs: /usr/sbin/vlogger
the above two items I have seen mentioned in other threads where the problem appeared similar.