You are not on the list to send emails to the address specified. There is little or no chance of resolving this issue without contacting the recipient and having them whitelist you. I then added the properties listed below to the file. These properties can be found in the Redback config-defaults.properties.A 553 email error is normally related to SMTP authentication not being used. reason -301 negative response from SMTP server ( RSP^553 Relaying blocked at this site.[£!You should receive a bounce-back message from the server with a variation of email error 553 in the subject, and the body should contain your original message that you attempted to deliver. We host emails but we don't provide support for email setup on an AS/400.
Pro: An SPF record can prevent incoming spoofed senders in the SMTP MAIL FROM: command. Con: SPF does not check whether the address issued during the SMTP MAIL FROM: command matches the address in the From: line of the message headers.
To block a domain as a sender in the Client portal: Pro: Rejects mail during the initial SMTP conversation at the Email Security.cloud server in response to SMTP RCPT TO: command. Con: Does nothing to prevent backscatter (NDRs from another domain which accepted a message with a spoofed sender containing your domain name).
To attempt to prevent backscatter, see User receiving bounce notification for email they did not send (Backscatter).
We would need the exact error message you're getting, the recipient name, and the account name (if you are an In Motion Hosting customer). Best Regards, TJ Edens Hi all I have problem with my outlook 2007, this case i can connect to zimbra pop3 by outlook but cannot send out.
If you wish to handle this issue privately please contact our live technical support team via a support ticket. i already use smtp port 25, 465 and 587 but still cannot send out the msg.