Bounce code ES000001
What the knowledge base's own tables say about this code, and which articles say it — a description of the reply, never a placement prediction.
This line comes from a knowledge base article on Comcast, not on the standard.
- Meaning
- Sending from a dynamic or residential IP address inside Comcast's network. Subscribers may send only through smtp.comcast.net
- Next step
- This block cannot be lifted. Use Comcast webmail or its submission service, or contact Commercial Services (support_biz@cable.comcast.com) to run a server
From Comcast / Xfinity — Postmaster: Error Codes, Rate Limits, Unblocking · Policy error codes (ES, DM)