I am using Cloudflare.
It is a reverse proxy service, which will make a lot of requests.
I think I am hitting a limit, as I am randomly getting Errof 521 from Cloudflare.
One of the reasons stated on their site for such issues is having mod_antiloris and mod_reqtimeout enabled.
I know as a fact my server is not going down every 5 minutes or other pageview.
The page on the Cloudflare KB is https://support.cloudflare.com/hc/en-us/articles/200171916-Error-521-Web-server-is-down
Here is what I did (Google Cloud Compute Engine)
SSH into the server
Find the line
LoadModule reqtimeout_module modules/mod_reqtimeout.so
and turn it into:
#LoadModule reqtimeout_module modules/mod_reqtimeout.so
/opt/bitnami/ctlscript.sh restart apache