Thank you for creating the ticket!
When accessing the environment configured with Spectrum (Application Type: HTTPS) with a WEB browser (chrome), the following error is displayed.
When checking the communication at this time with the capture tool, CloudFlare responds to ClientHello with the following error instead of ServerHello.
TLSv1 Record Layer: Alert (Level: Fatal, Description: Handshake Failure)
Content Type: Alert (21)
Version: TLS 1.0 (0x0301)
Level: Fatal (2)
Description: Handshake Failure (40)
I tried it with the openssl command and it was the same.
#openssl s_client -connect test.mydomain: 443 -msg
>>> ??? [length 0005]
16 03 01 01 39
>>> TLS 1.3, Handshake [length 0139], ClientHello
<<< ??? [length 0005]
15 03 01 00 02
<<< TLS 1.3, Alert [length 0002], fatal handshake_failure
Interestingly, I was able to establish an SSL connection by resolving the name and specifying the CNAME I got with the openssl command as -servername as below.
openssl s_client -connect test.mydomain: 443 -servername 123abcd.pacloudflare.com -msg