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ISSUE:
An inbound message is deferred with the following error code:
451 STARTTLS is required for this sender - psmtp
RESOLUTION:
The recipient domain uses Policy-Enforced TLS and requires that the sender send to them via TLS. This message was sent via unencrypted SMTP: no STARTTLS command was offered.
TIP: You can configure administrator alerts for TLS message delivery failures. For instructions, see:
http://www.postini.com/webdocs/encrypt/en_US/encrypt_admin/connection_alerts.html
For complete information about Message Encryption and Policy Enforced TLS, see following:http://www.postini.com/webdocs/encrypt/en_US/encrypt_admin
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