Oh, I see now the problem with HTTP (port 80) is due to a Palo Alto brand firewall. If you don't know about one your network support will.
I can reach your domain using a test URL similar to an HTTP Challenge. But, if I have a user-agent string similar to Let's Encrypt the request fails.
You must enable the "acme-protocol" in the Palo Alto's Applications setting.
We have seen many of these problems but not that many this year. Although, we have now seen a few in recent months so I hope this again does not become frequent. For another recent thread see: Renewal stopped working - #5 by MikeMcQ
Show this to your network support. Both of these curl requests should get a '404'
# Default curl user-agent gets expected 404
curl -i http://bote1.hacettepe.edu.tr/.well-known/acme-challenge/Test404
HTTP/1.1 404 Not Found
Server: Apache/2.4.58 (Ubuntu)
# With a Let's Encrypt user-agent it fails
curl -i http://bote1.hacettepe.edu.tr/.well-known/acme-challenge/Test404 -A "Mozilla/5.0 (compatible; Let's Encrypt validation server; +https://www.letsencrypt.org)"
curl: (56) Recv failure: Connection reset by peer