I am getting this since 2 days. routes error in php please

Uncaught Exception: No routes found for this Uri in C:\xampp\htdocs\PDO\core\router.php:23 Stack trace: #0 C:\xampp\htdocs\PDO\index.php(14): Router->direct('PDO') #1 {main} thrown in C:\xampp\htdocs\PDO\core\router.php on line 23.

I am not getting this since two days. help with this please.