diff --git a/src/Http/Router.php b/src/Http/Router.php
index 95f967b..e97cb9a 100644
--- a/src/Http/Router.php
+++ b/src/Http/Router.php
@@ -63,7 +63,7 @@ private function get_current_route(): string {
 
 		// Requested URI relative to WP install.
 		$uri = isset( $_SERVER['REQUEST_URI'] ) ? esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '';
-		$uri = str_replace( $installed_dir, '', $uri );
+		$uri = $installed_dir ? str_replace( $installed_dir, '', $uri ) : $uri;
 
 		$route = strtok( $uri, '?' );