Found it. Rewrite rule on the server for a previous security issue related to “themes.php” was in place.
Sorry for the bother.
OK, Ive confirmed I have version 2.3.3 and that the themes.php and theme-editor.php files are located on the server in the wp-admin diectory.
I reloaded those files to be sure they werent corrupt.
I still get the same 401 error.
Any other ideas?
