diff --git a/xero_python/api_client/oauth2.py b/xero_python/api_client/oauth2.py
index ca7aab20..f2277425 100644
--- a/xero_python/api_client/oauth2.py
+++ b/xero_python/api_client/oauth2.py
@@ -213,7 +213,7 @@ def can_refresh_access_token(self):
         """
         return (
             self.refresh_token
-            and isinstance(self.scope, (list, tuple))
+            and isinstance(self.scope, (list, tuple, str))
             and self.client_id
             and self.client_secret
         )