Error when Pushing: "... not allowed to push code to protected branches on this project"

I created a subproject on Maven, and added my code, as we talked with Mr. Kusmenko.

However, when I try to push, I get the following errors: remote: GitLab: You are not allowed to push code to protected branches on this project.

Normally, I would have created another branch and would push there, but as far as I remember, this is not what I told by Kusmenko.

For a temporary fix, I am temporarily creating a branch for BatteryInterface group and I will push my code there.