Or rather, you have had coolprop folder/directory in your bucket, so the URL should be like gcp.yourdomain.com/coolprop/file.js (or coolprop.yourdomain.com/coolprop/file.js if bucket name contains coolprop and you have directory coolprop inside it and also CNAME coolprop at the DNS tab of Cloudflare dashboard).
Your CNAME record is gcp.
It should be named as same as your bucket coolprop to make it work.
Or, better way to re-check and rename your bucket to gcp.yourdomain.com - must contain bucket-name.yourdomain.com (actual, this here is an example maybe you are missing a domain name part in your bucket name?).
Not needed and actually would cause some issues I think.
I would better if I want to serve static website from a bucket, create another bucket.
Screenshot of Google Cloud Platform → Google Storage, where your bucket is (to see if the name of the bucket is the gcp.ganibganapathi.com)
Screenshot of your DNS tab where the CNAME gcp record can be seen () and pointed to c.storage.googleapis.com
Screenshot of options for the Bucket (if it is public online, etc.) just in case if missing Permissions → Storage Object Viewer → AllUsers?, etc.
@fritex, just wanted to say thank you as it worked after fixing the error you spotted. There was one additional step - I had to verify I am the owner of the coolprop.ganbganapathi.com on the GCS Webmaster Central site. Once that was done, I was all set.