Error while running make build command

I am following the link. After running make build command it throws me this error :

Fetch or update
Traceback (most recent call last):
File "/home/onlykingkd/training/backend/venv/bin/mxdev", line 8, in
File "/home/onlykingkd/training/backend/venv/lib/python3.10/site-packages/", line 436, in main
File "/home/onlykingkd/training/backend/venv/lib/python3.10/site-packages/", line 351, in fetch
File "/home/onlykingkd/training/backend/venv/lib/python3.10/site-packages/libvcs/", line 189, in update_repo
File "/home/onlykingkd/training/backend/venv/lib/python3.10/site-packages/libvcs/", line 178, in obtain, log_in_real_time=True)
File "/home/onlykingkd/training/backend/venv/lib/python3.10/site-packages/libvcs/", line 119, in run
return run(
File "/home/onlykingkd/training/backend/venv/lib/python3.10/site-packages/libvcs/", line 200, in run
raise exc.CommandError(output=output, returncode=code, cmd=cmd)
libvcs.exc.CommandError: Command failed with code 128: git clone --progress ssh:// /home/onlykingkd/training/backend/sources/
Cloning into '/home/onlykingkd/training/backend/sources/' Permission denied (publickey).fatal: Could not read from remote repository.Please make sure you have the correct access rightsand the repository exists.
make: *** [Makefile:40: build] Error 1

This error was resolved after I added SSH Key to my github acount