fedpkg clone -a kernel failed

[Sampson Fung]

I am trying to build custom kernel on Fedora-34 following this quick-doc
https://docs.fedoraproject.org/en-US/quick-docs/kernel/build-custom-kernel/

I got error:
# fedpkg clone -a kernel
Cloning into 'kernel'...
remote: Enumerating objects: 2656, done.
remote: Counting objects: 100% (2656/2656), done.
remote: Compressing objects: 100% (926/926), done.
fetch-pack: unexpected disconnect while reading sideband packet 
fatal: early EOF
fatal: fetch-pack: invalid index-pack output
Could not execute clone: Failed to execute command.

This is my first time trying to do that.

Please help.