Site down after trying fix "issues" " "Disable trackbacks and pingbacks"

my site went down for a moment after i click "disable pingback" in the Hardener section.
i checked my cPanel and found that memory and i/o hit the limit, which is 512mb and 1024kbps. not sure how is related with i/o though....
my site came back live after around 5mins, and i check back the hardener, "Disable trackbacks and pingbacks" issue still exsit