The domain www.flystore.net is being served through Cloudflare CDN. Any Let's Encrypt certificate installed on the origin server will only encrypt traffic between the server and Cloudflare. It is strongly recommended that the SSL option 'Full SSL (strict)' be enabled.
https://support.cloudflare.com/hc/en-us/articles/200170416-What-do-the-SSL-options-mean-
Requests made to the domain
Request to: www.flystore.net/2606:4700:3037::6815:5314, Result: [Address=2606:4700:3037::6815:5314,Address Type=IPv6,Server=cloudflare,HTTP Status=404], Issue:
Trace:
@0ms: Making a request to http://www.flystore.net/.well-known/acme-challenge/letsdebug-test (using initial IP 2606:4700:3037::6815:5314)
@0ms: Dialing 2606:4700:3037::6815:5314
@1910ms: Server response: HTTP 404 Not Found
Request to: www.flystore.net/2606:4700:3036::ac43:a752, Result: [Address=2606:4700:3036::ac43:a752,Address Type=IPv6,Server=cloudflare,HTTP Status=404], Issue:
Trace:
@0ms: Making a request to http://www.flystore.net/.well-known/acme-challenge/letsdebug-test (using initial IP 2606:4700:3036::ac43:a752)
@0ms: Dialing 2606:4700:3036::ac43:a752
@2119ms: Server response: HTTP 404 Not Found
Request to: www.flystore.net/172.67.167.82, Result: [Address=172.67.167.82,Address Type=IPv4,Server=cloudflare,HTTP Status=404], Issue:
Trace:
@0ms: Making a request to http://www.flystore.net/.well-known/acme-challenge/letsdebug-test (using initial IP 172.67.167.82)
@0ms: Dialing 172.67.167.82
@2011ms: Server response: HTTP 404 Not Found
Request to: www.flystore.net/104.21.83.20, Result: [Address=104.21.83.20,Address Type=IPv4,Server=cloudflare,HTTP Status=404], Issue:
Trace:
@0ms: Making a request to http://www.flystore.net/.well-known/acme-challenge/letsdebug-test (using initial IP 104.21.83.20)
@0ms: Dialing 104.21.83.20
@1686ms: Server response: HTTP 404 Not Found
A and AAAA records found for this domain
www.flystore.net. 0 IN A 172.67.167.82
www.flystore.net. 0 IN A 104.21.83.20
www.flystore.net. 0 IN AAAA 2606:4700:3037::6815:5314
www.flystore.net. 0 IN AAAA 2606:4700:3036::ac43:a752
Challenge update failures for www.flystore.net in order https://acme-staging-v02.api.letsencrypt.org/acme/order/5751349/4462259724
acme: error code 403 "urn:ietf:params:acme:error:unauthorized": 2606:4700:3036::ac43:a752: Invalid response from http://www.flystore.net/.well-known/acme-challenge/w296b9dkdid6E6Su9327uj3_mQr8GOBRXX5uU2sDKb4: 404