After changing the site domain, I found out that the text editor for both Posts and Pages are missing.
There is this remark: “You are currently editing the page that shows your latest posts“
And I also have problem with Media Library, when I tried to set up Site Identity. After clicking the “Save and Publish” button, the favicon did not appeared.
Then when I went back to select image, there is no images in the library. just a grey box. And it hung. The arrow icon kept spinning.