Creating new repo from existing local git repo fails

[learningleaflet]

I'm using Git on Windows 10. I followed the step from https://confluence.atlassian.com/bitbucketserver/importing-code-from-an-existing-project-776640909.html by running

git remote add bitbucket https://learningleaflet@bitbucket.org/learningleaflet/learningleaflet.git

git push --all bitbucket
To https://bitbucket.org/learningleaflet/learningleaflet.git

Afterwards I got the error:

! [rejected] master -> master (non-fast-forward)
error: failed to push some refs to 'https://bitbucket.org/learningleaflet/learningleaflet.git'
hint: Updates were rejected because the tip of your current branch is behind
hint: its remote counterpart. Integrate the remote changes (e.g.
hint: 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

Given that I already have a history of commits I don't want to checkout the new empty branch and lose my existing commit history by moving over. How do I tell BitBucket to accept the the upload/push of my local git repo?

[learningleaflet]

It turned out that the documentation was incomplete. It seems creating a repo with the default setting makes this not work. After putting in a branch name and deciding not to add .gitignore it worked. Maybe adding the .gitignore creates a commit that makes the whole process fail.