video media encoder addframe texture format 5 expected to be 4

hello, im trying to load in a bunch of png images and make a video of them but when i try to add the frame to the encoder i get this error: VideoMediaEncoder::AddFrame texture format 5 expected to be 4.

this is the code i use to load in and add the pictures to the encoder:

 IEnumerator EncodeImages()
 {
     VideoTrackAttributes videoAttr = new VideoTrackAttributes
     {
         frameRate = new MediaRational(30),
         width = (uint)equirect.width,
         height = (uint)equirect.height,
         includeAlpha = false
     };

     Texture2D tex = new Texture2D(equirect.width, equirect.height, TextureFormat.RGB24, false);
     index = 0;
     using (MediaEncoder encoder = new MediaEncoder("C:/Users/Lars/Desktop/Images/ " + "my_movie.mp4", videoAttr, null))
     {
         while(index < amountOfFrames)
         {
             yield return StartCoroutine(LoadPNG("C:/Users/Lars/Desktop/Images/ " + "photo " + index.ToString() + ".png"));
             encoder.AddFrame(loadedTex);
             index++;
         }
         UnityEditor.EditorApplication.isPlaying = false;
         yield return null;
     }
 }
 
 
 IEnumerator LoadPNG(string filePath)
     {
         loadedTex = new Texture2D(equirect.width, equirect.height);
         byte[] fileData;
 
         if (File.Exists(filePath))
         {
             fileData = File.ReadAllBytes(filePath);
             //tex = new Texture2D(2, 2);
             yield return loadedTex.LoadImage(fileData);
         }
         else
         {
             Debug.LogError("file at: " + filePath + "doesn't exist");
         }
         yield return null;
     }

i really hope someone can help me, i've been stuck at this for 2 days now.