Do gifs just not work?

The uploaded image is just a test, its supposed to be my profile banner but with animated fire but when I try to upload it as my banner I get a timeout error (jerboa only shows a bit of that error and doesnt let me copy its text) and its always a broken image in previews

Also, the file is .gif but after uploading the link says .webm? Is that normal?

I've seen other people with animated banners and pfps but they were on other instances so I guess it might be an issue on this instance