diff --git a/src/Router.php b/src/Router.php
index 61f8737..b69966f 100644
--- a/src/Router.php
+++ b/src/Router.php
@@ -46,9 +46,11 @@
 
 			// Return HTML page if supported by client
 			if ($_SERVER["HTTP_ACCEPT"] === "*/*" || strpos($_SERVER["HTTP_ACCEPT"] ?? "", "text/html") !== false) {
+				header("Content-Type: text/html", true);
 				die(sprintf(file_get_contents(__DIR__ . "/error.html"), $error->value, $error->name));
 			}
 
+			header("Content-Type: text/plain", true);
 			die($error->name);
 		}