The chances are that you have arrived here because you have received a bounce back email message from us. 

This happens when an email is sent to one of our clients and a rule is triggered by the recipients preferred configuration.

We have identified the most common bounce back email messages and listed how these occur below.

MessageLabs clients can log into ClientNet to troubleshoot in greater detail.

553-Message filtered The error message indicates that your email was blocked as spam by our Signaturing anti-spam filter. Please try the following steps to resolve the issue: I. Check if your sending IP is on any black lists. A good place to check this is http://www.dnsstuff.com. This will be able to show any 3rd party lists that may have received spam from your mail server. If your IP address is on any block lists, please request for removal, wait 24 hours and then try to resend your email. II. Ensure your mail server is not open relay - http://www.abuse.net/relay.html. III. If your internet line is provided by DSL or Cable that shares IP’s with residential users, please ensure your mail server sends to your ISP’s smart host instead of direct to the internet. This reduces the potential of your email as being detected in error as coming from a Trojan infected home user machine. IV. Ensure the email you are sending does not contain any spam content (i.e. forwarded spam or ‘spamvertised’ URL’s). V. Ensure your mail server is configured correctly. VI. Ensure you have no virus infected machines on your network that are being used to send spam through your mail server. VII. Ensure you have no exploitable web scripts on your web servers that could be abused to send spam. The most commonly used one is PHP contact scripts which spammers can easily abuse the PHP “mail()” function to send what they want. VIII. Make sure any ‘opt-in’ newsletters contain an ‘opt-out’ link to be certain users can easily unsubscribe. If the problem persists, please contact the recipient by other means (e.g. fax or phone) and request that your email address be added to their approved senders list through the MessageLabs ClientNet Web portal.

553-mail rejected because your IP is in RBL/RSS/DUL This error message indicates that your public IP address has been put on a block list by the RBL, RSS or DUL block lists. To resolve this issue, please request to have your IP removed from the list at http://www.mail-abuse.com/lookup.html wait 24 hours and then try to resend your email. If the problem persists, please contact the recipient by other means (e.g. fax or phone) and request for your email address to be added to his approved senders list through the MessageLabs ClientNet web portal.

Sorry, your IP address has been blacklisted The error message indicates that your IP address is on the recipient’s private block list. Please contact the recipient by other means (eg fax or phone) and request for your email address to be added to his approved senders list through the MessageLabs ClientNet web portal.

Sorry, your domain has been blacklisted The error message indicates that your domain is on the recipient’s private block list. Please contact the recipient by other means (e.g. fax or phone) and request for your email address to be added to his approved senders list through the MessageLabs ClientNet web portal.

Sorry, your email address has been blacklisted The error message indicates that your email address is on the recipient’s private block list. Please contact the recipient by other means (e.g. fax or phone) and request for your email address to be added to his approved senders list through the MessageLabs ClientNet web portal.

550 Invalid recipient The error message indicates that you have sent an email to an invalid address at the recipient’s domain. Please double-check the email address for any spelling errors. If you believe the address is correct, please wait 4-6 hours and then try to resend your email. If the problem persists, please contact the recipient by other means (e.g. fax or phone) to ask for further assistance. you are trying to use me [server-x.tower-xx.messagelab] as a relay The error message indicates one of the following issues: * Your DNS server has cached the recipient’s old MX record * You are trying to relay outbound emails through MessageLabs from an incorrect IP address * The recipient’s domain has an incorrect MX record * The recipient’s email address contains invalid characters Please contact your administrator or your ISP to refresh your DNS server and then try to resend your email again. If the problem persists, please contact the recipient by other means (e.g. fax or phone) for further assistance.

550 Invalid recipient The error message indicates that you have sent an email to an invalid address at the recipient’s domain. Please double-check the email address for any spelling errors. If you believe the address is correct, please wait 4-6 hours and then try to resend your email. If the problem persists, please contact the recipient by other means (e.g. fax or phone) to ask for further assistance. you are trying to use me [server-x.tower-xx.messagelab] as a relay The error message indicates one of the following issues: Your DNS server has cached the recipient’s old MX record You are trying to relay outbound emails through MessageLabs from an incorrect IP address The recipient’s domain has an incorrect MX record The recipient’s email address contains invalid characters Please contact your administrator or your ISP to refresh your DNS server and then try to resend your email again. If the problem persists, please contact the recipient by other means (e.g. fax or phone) for further assistance.

I have not yet been able to deliver your message The error message indicates that the MessageLabs’ server was not able to deliver the email to the recipient’s server so it has queued the email for redelivery at a later time. This can be caused by the recipient’s mail server being unavailable at the time. We will continue to try to redeliver the email. Please contact your administrator for more details or contact the recipient by other means (e.g. fax or phone) for further assistance.

Connection Refused or Connection Deferred The error message indicates that your email may have been blocked as spam by our SMTP traffic shaping filter. Please try the following steps to resolve the issue: I. Please check with your administrator or ISP that your mail server is not an open relay. An open relay tester tool can be found at: http://abuse.net/relay.html If your mail server is an open relay, please fix the open relay, wait 24 hours and then try to resend your email. II. Please check with your administrator or ISP that your IP address is not on any spam block lists. A spam database lookup tool can be found at: http://www.dnsstuff.com/ If your IP address is on any block lists, please request for removal, wait 24 hours and then try to resend your email. If the problem persists, please contact the recipient by other means (e.g. fax or phone) and request for your email address to be added to his approved senders list through the MessageLabs ClientNet web portal.

460 too many messages The error message indicates that your company or ISP exceeded the number of messages allowed in the same connection. Please try resending your message. If the problem persists, please contact your IT administrator or ISP.

501 Connection rejected by policy [1] Your company/ISP mail server may not comply with RFC 2821 (see http://www.faqs.org/rfcs/rfc2821.html). Please contact your IT administrator or ISP. If the problem persists, please contact the recipient.

450 Requested action aborted [3] The error message indicates a temporary error. Please try resending your message. If the problem persists, please contact your IT administrator or ISP.

550 Requested action aborted [4] The format of your message did not comply with RFC 2822 (see http://www.faqs.org/rfcs/rfc2822.html). Please contact your IT administrator or ISP. If the problem persists, please contact the recipient.

450 Requested action aborted [6] The error message indicates a temporary error. Please try resending your message. If the problem persists, please contact your IT administrator or ISP.

450 Requested action aborted [7] The error message indicates a temporary error. Please try resending your message. If the problem persists, please contact your IT administrator or ISP.

421 too busy The error message indicates a temporary error. Please try resending your message. If the problem persists, please contact your IT administrator or ISP.

553-sorry, your envelope sender is in my badmailfrom list The error message indicates that you are sending from an email address that has been blocked by MessageLabs. Please check with your administrator or your ISP that you’re not sending out any spam emails. Please also check that any auto forwarding or out of office message feature has been turned off if currently enabled. Please wait 24 hours and then try to resend your email. If the problem persists, please contact the recipient by other means (e.g. fax or phone) for further assistance.

Sorry, your email address (addr) has been blacklisted I. Please check with your administrator or ISP that your mail server is not in open relay. An open relay tester tool can be found at: http://abuse.net/relay.html If your mail server is an open relay, please fix the open relay, wait 24 hours and then try to resend your email. II. Please check with your administrator or ISP that your IP address is not on any spam block lists. A spam database lookup tool can be found at: http://www.dnsstuff.com/ If your IP address is on any block lists, please request for removal, wait 24 hours and then try to resend your email. If the problem persists, please contact the recipient by other means (e.g. fax or phone) for further assistance.

Sorry, your IP address (ip-addr) has been blacklisted I. Please check with your administrator or ISP that your mail server is not in open relay. An open relay tester tool can be found at: http://abuse.net/relay.html If your mail server is an open relay, please fix the open relay, wait 24 hours and then try to resend your email. II. Please check with your administrator or ISP that your IP address is not on any spam block lists. A spam database lookup tool can be found at: http://www.dnsstuff.com/ If your IP address is on any block lists, please request for removal, wait 24 hours and then try to resend your email. If the problem persists, please contact the recipient by other means (e.g. fax or phone) for further assistance.

Recipient mailbox is not allowed The error message indicates that you have sent an email to an invalid address at the recipient’s domain. Please double check the email address for any spelling errors. If you believe the address is correct, please wait 4-6 hours and then try to resend your email. If the problem persists, please contact the recipient by other means (e.g. fax or phone) to ask for further assistance.

501 Connection rejected by policy [7] The error message indicates a permanent error. Please try resending your message. If the problem persists, please contact your IT administrator or ISP.

501 Connection rejected by policy [8] Your company/ISP mail server may not comply with RFC 2821 (see http://www.faqs.org/rfcs/rfc2821.html). Please contact your IT administrator or ISP. If the problem persists, please contact the recipient.

Connection Refused or Connection Deferred The error message indicates that your email may have been blocked as spam by our SMTP traffic shaping filter. Please try the following steps to resolve the issue: I. Please check with your administrator or ISP that your mail server is not an open relay. An open relay tester tool can be found at: http://abuse.net/relay.html If your mail server is an open relay, please fix the open relay, wait 24 hours and then try to resend your email. II. Please check with your administrator or ISP that your IP address is not on any spam block lists. A spam database lookup tool can be found at: If your IP address is on any block lists, please request for removal, wait 24 hours and then try to resend your email. If the problem persists, please contact the recipient by other means (e.g. fax or phone) and request for your email address to be added to his approved senders list through the MessageLabs ClientNet web portal.