Hi Bakam,
You can activate your MATLAB license, either directly from MATLAB or through your MathWorks Account.
Please look at the links I have attached below for more details regarding this.
Official documentation for activating MATLAB software – https://www.mathworks.com/help/matlab/matlab_env/manage-your-licenses.html#:~:text=to%20restart%20MATLAB.-,Activate%20Software,-The%20simplest%20way
Activating MATLAB license manually - https://www.mathworks.com/help/install/ug/activate-matlab-installation-manually.html
Hope this resolves your issue!