I use Cloudflare with 2 sites: The first one is a custom PHP / HTML website and the second one is a Mediawiki based (latest version 1.37) one.
Fom the last 3 weeks of November till now I was getting a constant very slow load time for the Mediawiki website fixed at 100 seconds and I was also getting the same issue with the other website with the same 100 sec delay, but randomly, not constantly as with the other one.
Today, I changed the name servers of the Mediawiki website to the ones of the hosting company’s and the problem was resolved instantly. I kept the Cloudflare name servers for the other website and the problem continued to exist in the same manner as previously.
Afterwards I again changed the name servers of the Mediawiki website back to Cloudflare’s ones and the delay reappeared.
For some reason the Mediawiki website constantly takes 100 seconds for loading when using Cloudflare.
I had the TLS encryption set to Full (strict) for both sites. There are Let’s Encrypt certificates available for both sites on the origin server. I changed the policy to Flexible and afterwards to Full (not strict) for the Mediawiki website but the problem persists.
When I use https://www.cloudflare.com/diagnostic-center/ I get an “slow_ttfb_on_cache” error.
Any idea which setting is causing this major delay to the websites’ loading time?