Merge pull request #7001 from segmentio/jfoskin-patch-4

Update custom domain downtime info.md

Author: stayseesong

src/connections/sources/catalog/libraries/website/javascript/custom-proxy.md

@@ -66,6 +66,8 @@ A Segment Customer Success team member will respond that they have enabled this
 > info ""
 > The **Host Address** field does not appear in source settings until it's enabled by Segment Customer Success.
 
+There should be no downtime once the setup is complete, as the default Segment domains continue to work alongside the customer's domains. 
+
 
 ## Custom CDN / API Proxy