diff --git a/api/mailinabox.yml b/api/mailinabox.yml
index c244d673..6e5d4daa 100644
--- a/api/mailinabox.yml
+++ b/api/mailinabox.yml
@@ -284,7 +284,7 @@ paths:
         200:
           description: Successful operation
           content:
-            application/json:
+            text/html:
               schema:
                 $ref: '#/components/schemas/SystemRebootResponse'
         403: