Repeated 403 console error when changing siteurl

[markusfinell]

When I change the siteurl from domain.com/wp to just domain.com, I get a repeating 403 error in the console when I'm in the block editor. The response is: {"code":"rest_cookie_invalid_nonce","message":"Cookie check failed","data":{"status":403}}

I seem to remember seeing a tutorial on how to setup this wp skeleton years ago, and the person did change some constant in the wp-config to set the siteurl to just the root domain.

Any ideas?