Child sites cannot add featured images

As the title, I can't add any featured images on any Child Site. I set the `SITE_ID` is `1` so that I can use the images on the center site, and then the problem comes. 
Anything on the center site is OK. The problem only appears on the child site. 
Btw, I can add images with Gutenberg on any site in the network. Do you know how to deal with it? Thanks !