The REST api encountered an unexpected result 404 WordPress Error
I spend several hours over two days trying to figure out what this error was.
I tried refreshing permalinks, deleting the .htaccess file and all sorts.
In the end, I found this helpful post on the WordPress support forums.
I narrowed the issue to a URL issue as it could not find the URL.
From the post, the suggestion was to change the permalinks to custom and add:
/index.php/%postname%/
I did that, saved and it worked.
The only issue now was every page had .index.php in front. I went back and changed to my standard permalinks setting “Post Name”, saved and now it works fine.