After changing the nameservers the site immediately stopped loading. I waited for 24 hours but still it isn’t solved.
However, meanwhile I got these two errors. However, I contacted the inmotionhosting where my site is hosted and they said, it’s a problem from the Cloudflare side.
This zone is in a pending state and contains proxied records. Until the zone is activated, DNS queries to be proxied records will expose the origin IP/hostname and traffic cannot be proxied through Cloudflare. For more information refer to Limitations for pending domains.