Cannot install new package using luarocks install

[M-Melodious]

I followed the steps provided here to install the lua torch. After installation when I tried installing new package it gives me following error.

`Installing https://raw.githubusercontent.com/rocks-moonscript-org/moonrocks-mirror/master/protobuf-1.1.2-0.rockspec...
Using https://raw.githubusercontent.com/rocks-moonscript-org/moonrocks-mirror/master/protobuf-1.1.2-0.rockspec... switching to 'build' mode
Cloning into 'protobuf-lua'...
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Error: Failed cloning git repository.`

My system is Ubuntu 20.04
Please help me to solve the error.