yarn install throws github.com[1: 127.0.0.1]: errno=Connection refused

When I executed yarn install, it throws:

error Command failed.
Exit code: 128
Command: git
Arguments: ls-remote --tags --heads https://github.com/frozeman/bignumber.js-nolookahead.git
Directory: /Users/pro/eth/hello-snap
Output:
fatal: unable to connect to github.com:
github.com[0: 127.0.0.1]: errno=Connection refused
github.com[1: ::1]: errno=Connection refused

I checked /etc/hosts, there was no 127.0.0.1 github.com or ::1 github.com.

And also I removed http.proxy by git config --global --unset http.proxy.

It bothered me a whole day Does anyone know how it comes?