Hello Mr. Akif, You cannot use any sky image as a panoramic background image, the images must be 360 degrees created in accordance with the panoramic coating logic and must be high resolution. For this purpose, you can choose one of the textures in the /sky folder under the program installation, or you can use another sky map created with the same logic. Here, it looks like you have used any sky image. Since the image is not prepared for this type of coating and is low resolution, the joint is visible from the point of view, and pixelizations occur.