diff --git a/src/Api.php b/src/Api.php
index d4756f6..3733e90 100644
--- a/src/Api.php
+++ b/src/Api.php
@@ -438,6 +438,8 @@ class Api {
 
     private function assertLoggedIn(): void
     {
+        $this->authenticator->refresh();
+
         if (!$this->isLoggedIn()) {
             throw new NotAuthenticatedException('You need to login first');
         }
diff --git a/src/Authentication/Authenticator.php b/src/Authentication/Authenticator.php
index c7671ac..d3e3ba1 100644
--- a/src/Authentication/Authenticator.php
+++ b/src/Authentication/Authenticator.php
@@ -9,7 +9,9 @@ abstract class Authenticator {
     abstract public function login(int $mglnr, string $password): self;
     abstract public function http(): PendingRequest;
     abstract public function isLoggedIn(): bool;
-    protected static $path = __DIR__.'/../../.cookies';
+    abstract public function refresh(): void;
+
+    protected static string $path = __DIR__.'/../../.cookies';
 
     public static function setPath(string $path): void
     {
diff --git a/src/Authentication/FakeCookie.php b/src/Authentication/FakeCookie.php
index f695ade..829bd65 100644
--- a/src/Authentication/FakeCookie.php
+++ b/src/Authentication/FakeCookie.php
@@ -85,6 +85,11 @@ class FakeCookie extends Authenticator {
         );
     }
 
+    public function refresh(): void
+    {
+        //
+    }
+
     public function assertNotLoggedIn(): void
     {
         Assert::assertFalse(
diff --git a/src/Authentication/MainCookie.php b/src/Authentication/MainCookie.php
index 795ffd7..3ab71bf 100644
--- a/src/Authentication/MainCookie.php
+++ b/src/Authentication/MainCookie.php
@@ -12,6 +12,8 @@ class MainCookie extends Authenticator {
 
     private FileCookieJar $cookie;
     private string $url = 'https://nami.dpsg.de';
+    private ?int $mglnr = null;
+    private ?string $password = null;
 
     public function login(int $mglnr, string $password): self
     {
@@ -19,6 +21,9 @@ class MainCookie extends Authenticator {
             return $this;
         }
 
+        $this->mglnr = $mglnr;
+        $this->password = $password;
+
         while ($file = $this->file()) {
             unlink($file);
         }
@@ -52,6 +57,13 @@ class MainCookie extends Authenticator {
         return ! $this->isExpired();
     }
 
+    public function refresh(): void
+    {
+        if ($this->mglnr && $this->password) {
+            $this->login($this->mglnr, $this->password);
+        }
+    }
+
     public function http(): PendingRequest
     {
         return Http::withOptions(['cookies' => $this->load()]);
diff --git a/tests/TestCase.php b/tests/TestCase.php
index 4dca63e..59da08c 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -44,13 +44,17 @@ class TestCase extends \Orchestra\Testbench\TestCase
         return Nami::login(123, 'secret');
     }
 
-    private function setupCookies(): void
+    protected function clearCookies(): void
     {
-        Authenticator::setPath(__DIR__.'/../.cookies_test');
-
         foreach (glob(__DIR__.'/../.cookies_test/*') as $file) {
             unlink($file);
         }
     }
 
+    private function setupCookies(): void
+    {
+        Authenticator::setPath(__DIR__.'/../.cookies_test');
+        $this->clearCookies();
+    }
+
 }
diff --git a/tests/Unit/CourseTest.php b/tests/Unit/CourseTest.php
index e21634c..57ba7d6 100644
--- a/tests/Unit/CourseTest.php
+++ b/tests/Unit/CourseTest.php
@@ -91,7 +91,7 @@ class CourseTest extends TestCase
     {
         $this->expectException(NotAuthenticatedException::class);
 
-        $courses = Nami::coursesFor(11111);
+        Nami::coursesFor(11111);
     }
 
     public function test_parses_failed_login(): void
diff --git a/tests/Unit/LoginTest.php b/tests/Unit/LoginTest.php
index 6a8a090..ae39b52 100644
--- a/tests/Unit/LoginTest.php
+++ b/tests/Unit/LoginTest.php
@@ -4,6 +4,7 @@ namespace Zoomyboy\LaravelNami\Tests\Unit;
 
 use Illuminate\Support\Facades\Http;
 use Zoomyboy\LaravelNami\Authentication\Auth;
+use Zoomyboy\LaravelNami\Fakes\CourseFake;
 use Zoomyboy\LaravelNami\LoginException;
 use Zoomyboy\LaravelNami\Nami;
 use Zoomyboy\LaravelNami\Tests\TestCase;
@@ -93,6 +94,19 @@ class LoginTest extends TestCase
         Http::assertSentCount(2);
     }
 
+    public function test_it_refreshes_login_when_a_cookie_of_an_existing_api_is_expired(): void
+    {
+        app(CourseFake::class)->forMember(11111, []);
+        Http::fake($this->fakeSuccessfulLoginForever());
+        $api = Nami::login(12345, 'secret');
+        $this->clearCookies();
+        $lastLogin = now()->subHours(2)->timestamp;
+        touch(__DIR__."/../../.cookies_test/{$lastLogin}.txt");
+
+        $courses = $api->coursesFor(11111);
+        $this->assertCount(0, $courses);
+    }
+
     public function test_it_fakes_login(): void
     {
         Auth::fake();
@@ -138,6 +152,14 @@ class LoginTest extends TestCase
         ];
     }
 
+    private function fakeSuccessfulLoginForever(): array
+    {
+        return [
+            'https://nami.dpsg.de/ica/pages/login.jsp' => Http::response('<html></html>', 200),
+            'https://nami.dpsg.de/ica/rest/nami/auth/manual/sessionStartup' => Http::response($this->successJson, 200),
+        ];
+    }
+
     private function fakeFailedLogin(): array
     {
         return [