diff --git a/CHANGELOG.md b/CHANGELOG.md
index ce5f9a2..862ff22 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## [Unreleased]
+
+### Fixed
+
+- User generated errors were interpreted as "not found" errors.
+
 ## 4.0.1 - 2026-03-19
 
 ### Fixed
diff --git a/src/Http/Router.php b/src/Http/Router.php
index 6deed48..ada236e 100644
--- a/src/Http/Router.php
+++ b/src/Http/Router.php
@@ -6,7 +6,6 @@
 use Innmind\Http\{
     ServerRequest,
     Response,
-    Response\StatusCode,
 };
 use Innmind\Router\{
     Component,
@@ -14,6 +13,8 @@
     Any,
     Handle,
     Respond,
+    Exception\NotFound,
+    Exception\NoRouteProvided,
 };
 use Innmind\Immutable\{
     Maybe,
@@ -45,24 +46,28 @@ public function __construct(
     public function __invoke(ServerRequest $request): Attempt
     {
         $recover = $this->recover;
+        $notFound = $this->notFound;
 
         /**
          * @psalm-suppress MixedArgumentTypeCoercion
          */
         $route = Route::of(
             Any::from($this->routes)
+                ->mapError(static fn($e) => match (true) {
+                    $e instanceof NoRouteProvided => new NotFound,
+                    default => $e,
+                })
+                ->otherwise(static fn(\Throwable $e) => Component::of(
+                    static fn($request) => $notFound
+                        ->filter(static fn() => $e instanceof NotFound)
+                        ->match(
+                            static fn($handle) => $handle($request),
+                            static fn() => Attempt::error($e),
+                        ),
+                ))
                 ->otherwise(Respond::withHttpErrors())
                 ->otherwise(static fn($e) => Handle::via(
                     static fn($request) => $recover($request, $e),
-                ))
-                ->or(Handle::via(
-                    fn($request, SideEffect $_) => $this->notFound->match(
-                        static fn($handle) => $handle($request),
-                        static fn() => Attempt::result(Response::of(
-                            StatusCode::notFound,
-                            $request->protocolVersion(),
-                        )),
-                    ),
                 )),
         );
 
diff --git a/tests/ApplicationTest.php b/tests/ApplicationTest.php
index 1b1059d..0b5d151 100644
--- a/tests/ApplicationTest.php
+++ b/tests/ApplicationTest.php
@@ -1406,4 +1406,40 @@ public function testRecoverRouteError(): BlackBox\Proof
                 $this->assertSame($expected, $response);
             });
     }
+
+    #[\Innmind\BlackBox\PHPUnit\Framework\Attributes\Group('wip')]
+    public function testRouteErrorIsNotSwallowed(): BlackBox\Proof
+    {
+        return $this
+            ->forAll(
+                Set::of(...ProtocolVersion::cases()),
+                Set::sequence(
+                    Set::compose(
+                        static fn($key, $value) => [$key, $value],
+                        Set::strings()->randomize(),
+                        Set::strings(),
+                    ),
+                )->between(0, 10),
+            )
+            ->prove(function($protocol, $variables) {
+                $expected = new \Exception;
+
+                $app = Application::http(Factory::build(), Environment::test($variables))
+                    ->service(Services::serviceA, static fn() => static fn() => Attempt::error($expected))
+                    ->routes(Routes::class);
+
+                $error = $app
+                    ->run(ServerRequest::of(
+                        Url::of('/foo'),
+                        Method::get,
+                        $protocol,
+                    ))
+                    ->match(
+                        static fn() => null,
+                        static fn($e) => $e,
+                    );
+
+                $this->assertSame($expected, $error);
+            });
+    }
 }