Screenshots are black

Hi everyone! I found a script that takes screenshot of a given rect but all of my screenshots are black. Why is that?

 public class ScreenshotTaker : MonoBehaviour
     {
         private int scrShotCount = 0;
         private Texture2D texture1, texture2;
         private int mWidth, mHeight;
         
         private Camera mCamera;
         // Start is called before the first frame update
         void Start()
         {
             mCamera = GetComponent<Camera>();
             mWidth = mCamera.pixelWidth;
             mHeight = mCamera.pixelHeight;
         }
     
         // Update is called once per frame
         void Update()
         {
             if (Input.GetKeyDown(KeyCode.Space))
             {
                 Debug.Log("ScreenshotTaker");
                 
                 if (scrShotCount == 0)
                 {
                     texture1 = RTImage();
                     scrShotCount++;
                 }
                 else if (scrShotCount == 1)
                 {
                     texture2 = RTImage();
                     scrShotCount = 0;
                     
                 }
             }
         }
         
         private Texture2D RTImage()
         {
             Rect rect = new Rect(0, 0, mWidth, mHeight);
             RenderTexture renderTexture = new RenderTexture(mWidth, mHeight, 24);
             Texture2D screenShot = new Texture2D(renderTexture.width, renderTexture.height, TextureFormat.RGBA32, false);
     
             mCamera.targetTexture = renderTexture;
             //mCamera.Render();
     
             RenderTexture.active = renderTexture;
             screenShot.ReadPixels(rect, 0, 0);
             
             screenShot.Apply();
             byte[] byteArray = screenShot.EncodeToPNG();
             System.IO.File.WriteAllBytes(Application.dataPath + "/CameraScreenshot.png", byteArray);
             mCamera.targetTexture = null;
             RenderTexture.active = null;
     
             Destroy(renderTexture);
             
             return screenShot;
         }

I have a second camera on my scene and that script is attached to that. Is it about resolution or anything else?