I have been trying to implement HTTPS on a kubernetes cluster on Google Cloud Platform. I cannot understand what else I need to check or look for. I am using a Google Managed certificate.

dig output

; <<>> DiG 9.11.5-P4-5.1+deb10u5-Debian <<>> demo.abhikube.tk
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 59409
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;demo.abhikube.tk.              IN      A

;; ANSWER SECTION:
demo.abhikube.tk.       300     IN      A       35.190.47.137

;; Query time: 47 msec
;; SERVER: 169.254.169.254#53(169.254.169.254)
;; WHEN: Sun Sep 12 10:00:45 UTC 2021
;; MSG SIZE  rcvd: 61

Command:- openssl s_client -connect demo.abhikube.tk:443 -tls1_2

CONNECTED(00000003)
write:errno=0
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 0 bytes and written 213 bytes
Verification: OK
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
SSL-Session:
    Protocol  : TLSv1.2
    Cipher    : 0000
    Session-ID:
    Session-ID-ctx:
    Master-Key:
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    Start Time: 1631440972
    Timeout   : 7200 (sec)
    Verify return code: 0 (ok)
    Extended master secret: no

I have tried multiple times but Google keeps showing FailedNotVisible. What else can I do to fix this? I am not an expert on ssl. Google doc said if the verify return is ok it should work..but it doesn't. The HTTP version works fine.

UPDATE:- I ran a check on https://dnssec-analyzer.verisignlabs.com/..it shows

No DS records found for abhikube.tk in the tk zone
	ns-cloud-e2.googledomains.com returns REFUSED for abhikube.tk/DNSKEY
	ns-cloud-e4.googledomains.com returns REFUSED for abhikube.tk/DNSKEY
	ns-cloud-e3.googledomains.com returns REFUSED for abhikube.tk/DNSKEY
	ns-cloud-e1.googledomains.com returns REFUSED for abhikube.tk/DNSKEY

Could this be because it is a free domain?Any inputs? http version works fine. Some added information https://dns.google/query?name=demo.abhikube.tk&rr_type=A&ecs=&disable_dnssec=true&show_dnssec=true