Some plugins and themes will try to connect back to your website like a visitor, often to scan the content of your website to check for things like configuration issues.
This does not work on InfinityFree. Websites on InfinityFree use a security system that blocks automated access to websites hosted here. This also affects WordPress trying to access it’s own website. Connections like that may result in a 403 Forbidden response, or receiving the HTML code for the security challenge.
Because of this:
I found that the Block Editor will still function without this REST API. There isn’t any issues when it comes down to this, so it should usually be ignored.