diff --git a/bingads/authorization.py b/bingads/authorization.py
index 3a1898bc..97589659 100644
--- a/bingads/authorization.py
+++ b/bingads/authorization.py
@@ -692,7 +692,7 @@ def __init__(self):
         (PRODUCTION, ADS_MANAGE):     'https://ads.microsoft.com/ads.manage offline_access',
         (PRODUCTION, BINGADS_MANAGE): 'bingads.manage',
         (SANDBOX, MSADS_MANAGE):      'https://api.ads.microsoft.com/msads.manage offline_access',
-        (SANDBOX, MSA_PROD):          'https://si.ads.microsoft.com'
+        (SANDBOX, MSA_PROD):          'https://si.ads.microsoft.com/msads.manage offline_access'
     }
 
     @staticmethod