diff --git a/controllers/CalendarApiController.php b/controllers/CalendarApiController.php
index 8d3db47e..7cf3d7e2 100644
--- a/controllers/CalendarApiController.php
+++ b/controllers/CalendarApiController.php
@@ -49,6 +49,7 @@ class CalendarApiController extends BaseApiController
 				$vCalendar->addEvent($vEvent);
 			}
 
+			ob_clean(); // Make sure to ONLY return the file
 			$response->write((new CalendarFactory())->createCalendar($vCalendar));
 			$response = $response->withHeader('Content-Type', 'text/calendar; charset=utf-8');
 			return $response->withHeader('Content-Disposition', 'attachment; filename="grocy.ics"');
diff --git a/controllers/FilesApiController.php b/controllers/FilesApiController.php
index 5dbca1ec..4ff4980c 100644
--- a/controllers/FilesApiController.php
+++ b/controllers/FilesApiController.php
@@ -49,6 +49,7 @@ class FilesApiController extends BaseApiController
 
 			if (file_exists($filePath))
 			{
+				ob_clean(); // Make sure to ONLY return the file
 				$response->write(file_get_contents($filePath));
 				$response = $response->withHeader('Cache-Control', 'max-age=2592000');
 				$response = $response->withHeader('Content-Type', mime_content_type($filePath));
@@ -80,6 +81,7 @@ class FilesApiController extends BaseApiController
 
 			if (file_exists($filePath))
 			{
+				ob_clean(); // Make sure to ONLY return the file
 				$response->write(file_get_contents($filePath));
 				$response = $response->withHeader('Cache-Control', 'max-age=2592000');
 				$response = $response->withHeader('Content-Type', mime_content_type($filePath));