If you are receiving the error:
550 5.7.1 [ESA] Sender blocked
it means the MailChannels system has detected extensive abuse originating from your email account.
Examples of abuse include:
- Spam email
- Bulk email
- High complaint rates
- Lots of invalid recipients
What can I do to unblock my account?
Please file a support request by following the instructions at:
Content retrieved from: https://support.appliedi.net/kb/a948/mailchannels-error-550-5_7_1-esa-sender-blocked.aspx.