failed to deploy to github pages

[kambing86]

just migrated to https://www.travis-ci.com/

then found that deployment to github pages always failing

repo: https://github.com/kambing86/npm-explorer

log here: https://api.travis-ci.com/v3/job/479273759/log.txt

travis_fold:start:dpl.3
Deploying application
Initialized empty Git repository in /tmp/d20210201-7869-1ktbpic/work/.git/
Repo created successfully
Switched to a new branch 'gh-pages'
An orphan branch gh-pages created successfully
cd -
cd /tmp/d20210201-7869-1ktbpic/work
Copying /home/travis/build/kambing86/npm-explorer/build contents to /tmp/d20210201-7869-1ktbpic/work (workdir: /tmp/d20210201-7869-1ktbpic/work)...
Configuring git committer to be Deployment Bot (from Travis CI) <deploy@travis-ci.org> (workdir: /tmp/d20210201-7869-1ktbpic/work)
Preparing to deploy gh-pages branch to gh-pages (workdir: /tmp/d20210201-7869-1ktbpic/work)
On branch gh-pages

Initial commit

nothing to commit (create/copy files and use "git add" to track)
fatal: ambiguous argument 'HEAD': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'
Doing the git push (workdir: /tmp/d20210201-7869-1ktbpic/work)...
Couldn't push the build to github.com/kambing86/npm-explorer.git:gh-pages

travis_fold:end:dpl.3
failed to deploy

[stale[bot]]

Thanks for contributing to this issue. As it has been 90 days since the last activity, we are automatically closing the issue. This is often because the request was already solved in some way and it just wasn't updated or it's no longer applicable. If that's not the case, please do feel free to either reopen this issue or open a new one. We'll gladly take a look again! You can read more here: https://blog.travis-ci.com/2018-03-09-closing-old-issues