Metamask integration with Quarkchain devnet is failing

I was following Quarkchain developer tutorial at link - It suggests as below

As an optional step, you can add our JRPC endpoint,, as a “Custom RPC” endpoint in MetaMask so that MetaMask will show your proper QKC token balance.

But when I proceed to do that on Google Chrome 91 with Metamask (9.7.0), I get error as “Could not fetch chain ID. Is your RPC URL Correct”? Attaching screenshot. Kindly guide.