diff --git a/tests/Integration/AuthorizationServerTest.php b/tests/Integration/AuthorizationServerTest.php
index 61aec75..1b148b2 100644
--- a/tests/Integration/AuthorizationServerTest.php
+++ b/tests/Integration/AuthorizationServerTest.php
@@ -387,7 +387,7 @@ public function testDifferentClientRefreshGrant(): void
         $response = $this->handleTokenRequest($request);
 
         // Response assertions.
-        $this->assertSame('invalid_request', $response['error']);
+        $this->assertSame('invalid_grant', $response['error']);
         $this->assertSame('The refresh token is invalid.', $response['error_description']);
         $this->assertSame('Token is not linked to client', $response['hint']);
     }
@@ -422,7 +422,7 @@ public function testExpiredRefreshGrant(): void
         $response = $this->handleTokenRequest($request);
 
         // Response assertions.
-        $this->assertSame('invalid_request', $response['error']);
+        $this->assertSame('invalid_grant', $response['error']);
         $this->assertSame('The refresh token is invalid.', $response['error_description']);
         $this->assertSame('Token has expired', $response['hint']);
     }
@@ -439,7 +439,7 @@ public function testRevokedRefreshGrant(): void
         $response = $this->handleTokenRequest($request);
 
         // Response assertions.
-        $this->assertSame('invalid_request', $response['error']);
+        $this->assertSame('invalid_grant', $response['error']);
         $this->assertSame('The refresh token is invalid.', $response['error_description']);
         $this->assertSame('Token has been revoked', $response['hint']);
     }
@@ -468,7 +468,7 @@ public function testInvalidPayloadRefreshGrant(): void
         $response = $this->handleTokenRequest($request);
 
         // Response assertions.
-        $this->assertSame('invalid_request', $response['error']);
+        $this->assertSame('invalid_grant', $response['error']);
         $this->assertSame('The refresh token is invalid.', $response['error_description']);
         $this->assertSame('Cannot decrypt the refresh token', $response['hint']);
     }