Unable to install dependencies of perseus GitHub repo

[Shubhendra Kushwaha]

When I try to install dependencies using yarn it is unable to find git@github.com:Khan/mathjax-renderer.git and  gives me following error

yarn install v1.22.19

error Command failed.

Exit code: 128

Command: git

Arguments: ls-remote --tags --heads g...@github.com:Khan/mathjax-renderer.git

Directory: /Users/shubhendra/aveti/perseus

Output:

ERROR: Repository not found.

Can anybody please help me to figure out the reason.

Thanks
Shubhendra