diff --git a/server/users/models.py b/server/users/models.py
index 7057057f..8fc62cfa 100644
--- a/server/users/models.py
+++ b/server/users/models.py
@@ -367,7 +367,10 @@ class License(models.Model):
         if not is_aware(expiry_date):
             expiry_date = make_aware(expiry_date)
 
-        return expiry_date >= now >= expiry_date - timedelta(days=licenses[isbn]['duration'])
+        try:
+            return expiry_date >= now >= expiry_date - timedelta(days=licenses[isbn]['duration'])
+        except KeyError: # this can happen if the platform changed, e.g. during local testing
+            return False
 
     def __str__(self):
         return f'License for role: {self.for_role}'