Hi Patryk,
It seems there might be a small typo in your function block. The correct function name is atan2d, not 'atand2'. After updating the function calls to atan2d, I tested your function block with a [4x4] matrix input, and the simulation executed without any errors.
For further clarification on the atan2d function, you can consult the following MATLAB documentation page:
Hope this helps.