diff --git a/airbyte-integrations/connectors/source-orb/source_orb/schemas/subscriptions.json b/airbyte-integrations/connectors/source-orb/source_orb/schemas/subscriptions.json
index 06d61daa35809..c341eb43cb384 100644
--- a/airbyte-integrations/connectors/source-orb/source_orb/schemas/subscriptions.json
+++ b/airbyte-integrations/connectors/source-orb/source_orb/schemas/subscriptions.json
@@ -13,7 +13,7 @@
       "type": "string"
     },
     "external_customer_id": {
-      "type": "string"
+      "type": ["null", "string"]
     },
     "start_date": {
       "type": ["null", "string"],