GitHub contributions' count

Hello. Dear all, please help me with contributions’ count.
I have approximately 400 commits, some pull requests and issues, but on the main page there is only 19 contributions. Why?

Did you change the email associated with your GH account?

GitHub’s way to associate commits to your account is via the email info found in a commit. So if you’re using a different email in your commits (e.g. because of different Git settings across machines or Git Apps), then Git won’t be able they were your commits.

Also, any Git rewrite operations that could delete your email from commits (e.g. someone else squashing your commits into one) would also result in those contributions counts being lost.

And then, of course: deleted (or archived!) repositories, etc.