IDENTIFIED: Nov/03/2023 - 5:00 PM EST
Our Engineering team identified an issue with mailchannel where customers are getting this error:
SMTP error from remote mail server after end of data: 550 5.7.1 [ESA] Sender blocked.
We are currently working on the issue and looking for a permanent fix.
We sincerely apologize for the inconvenience this might be causing on your side.
We will post further updates once available.