Dear Akihiro HASHIMOTO,
Thank you for the information very helpful. It was indeed a context type mismatch. I disabled SElinux, it worked, and then I enabled it, my expectation was that after enabling it I will get the same error, and I was prepared to get the error and fix it through changing the /var/www/html/moodle directory and its contents to the right context as required by SElinux theory. But after enabling it continue working and no error and the context was matching.
So, the source of the problem was the context. SElinux theory will help.
Cheers
Maharage