Website not loading after installing Cloudflare

the following window pops up when you try to open the site:

Unable to access siteCheck for typos in the hostname prodiag.com.ua.
If everything is correct, use the Windows Network Diagnostics tool.
DNS_PROBE_FINISHED_NXDOMAIN

Has anyone encountered such a problem?

There’s no records for prodiag.com.ua - take a screenshot of the DNS settings for that zone in the dashboard.

➜  ~ dig prodiag.com.ua @1.1.1.1

; <<>> DiG 9.18.1-1ubuntu1-Ubuntu <<>> prodiag.com.ua @1.1.1.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 46782
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;prodiag.com.ua.			IN	A

;; AUTHORITY SECTION:
prodiag.com.ua.		3600	IN	SOA	clyde.ns.cloudflare.com. dns.cloudflare.com. 2277319672 10000 2400 604800 3600

;; Query time: 40 msec
;; SERVER: 1.1.1.1#53(1.1.1.1) (UDP)
;; WHEN: Fri May 06 12:44:53 BST 2022
;; MSG SIZE  rcvd: 106

Screen in attache

That’s your registrar - you need to configure DNS in Cloudflare itself.

https://dash.cloudflare.com/?to=/:account/:zone/dns