A PHP session was created by a session_start() function call. This interferes with REST API and loopback requests. The session should be closed by session_write_close() before making any HTTP requests.
This error occurs because the session_start() function is creating a PHP session, which interferes with REST API and loopback requests in WordPress. To resolve this: Locate the session_start() code Search your theme or active plugins for the session_start() function. It may be in the theme’s functions.php file or in a custom plugin. Add session_write_close() after [...]