I do not know if it was like this from the beginning or not. After I upload my .gif files into my Wordpress library they shown as blank and even after using them in the webpage by any webpage builders(elementor, wpbakery, ...) it is still shown as blank images.
I appreciate your answers.
i looked for files permission its all set to 755 so I guess that is not the problem.
I found the solution and I will post it here so maybe other people like me may deal with problem in the future and figure out how to handle. It's simple. I didn't disable adblocker on my website. So I just did it today and it is all good.