AOL Error Codes
We provide the following error messages as a return bounce for every undeliverable email. You might receive a 554 permanent bounce or 421 temporary try again error. Please see below for explanation of our error codes.
REVERSE DNS ERRORS
We reject mail from IPs that have a generic reverse DNS (PTR Record). Common generic rDNS might contain in-addr.arpa, pool, dyn, dhcp etc. in the rDNS. Please contact your hosting provider and set a fully qualified domain name (FQDN) as your rDNS (ideally pointing to the sending domain).
RTR BLOCKS
554 RTR:BB
- AOL works with many ISPs to maintain lists of dynamic and residential IP addresses. Per our Email Guidelines, we do not accept mail from these addresses. If you are blocked by a RTR:BB error and have a fully qualified domain name (FQDN), please open a support request to lift the RTR:BB block. If you do not have a FQDN, please have your ISP create one for you and then open a support request.
554 RTR:CH
- A computer, or computers, on your network may be compromised and sending mail that matches the signature of known spam. Before opening a support request, ensure you have a fully qualified domain name, get approved for a complaint Feedback Loop, scan your system for compromises and secure any issues.
554 RTR:RD
- The reverse DNS of your IP Address is typical of a dynamic IP Address and/or has generated AOL member complaints. Ensure you have a fully qualified domain name and get approved for a Feedback Loop before opening a support request.
- rDNS must be in the form of a fully qualified domain name. rDNS containing in-addr.arpa are not acceptable, as these are merely placeholders for a valid PTR record. rDNS consisting of IP addresses are also not acceptable, as they do not correctly establish the relationship between domain and IP address.
- rDNS that may be similar to dynamic IP space (containing pool, dhcp, dyn, etc.) may be treated as suspect, and should therefore be changed to reflect a fully qualified domain name with a standard reverse DNS.
554 RTR:SC
- This error message is indicative of a block due to successive dynamic blocks issued against your IP address. Before opening a support request, ensure you have a fully qualified domain name as Reverse DNS, scan your system for compromises and secure any issues.
554 RTR:DU
- AOL uses the Spamhaus PBL to block mail from dynamic and residential IP addresses. Per our Email Guidelines, we do not accept mail from such addresses. If you believe your IP is listed in error, please contact your ISP directly and have them update their listing with the PBL. If:
- your ISP reports that the IP is correctly listed in the PBL, and that you should be able to send mail from it, or
- you were recently assigned IPs, have changed the rDNS on them, and allowed 48-72 hours for propagation time…and you are still getting the error, please open a support request.
554 RTR:GE
- This is a transient error indicating a technical issue on AOL’s side. Please wait 24 hours and then try to resend your mail. . This error would be auto resolved and does not require a support request.
554 RTR:BL
- This error message indicates that a permanent block has been placed against your IP due to poor reputation. If you were blocked recently, clean up your mailing list and apply for a complaint feedback loop before opening a support request.
HVU BLOCKS
554 HVU:B1
- There is at least one URL or domain in your mail headers/hostname that is generating substantial complaints from AOL members and is blocked on our end. To fix the problem, please open a support request.
554 HVU:B2
- There is at least one URL or domain in your email that is generating substantial complaints from AOL members and is blocked on our end. To fix the problem, please open a support request.
DNS BLOCKS
421 DNS:NR
- The Reverse DNS lookup for your IP address is failing. This could be a transient issue. Confirm the IP that sends your mail, and then check the rDNS of that IP using our troubleshooting tools. If it passes, please wait 24 hours and then try resending your mail before opening a support request.
- rDNS must be in the form of a fully qualified domain name. rDNS containing in-addr.arpa are not acceptable, as these are merely placeholders for a valid PTR record. rDNS consisting of IP addresses are also not acceptable, as they do not correctly establish the relationship between domain and IP address.
- rDNS that may be similar to dynamic IP space (containing pool, dhcp, dyn, etc.) may be treated as suspect, and should therefore be changed to reflect a fully qualified domain name with standard reverse DNS.
RLY BLOCKS
554 RLY:B1
- This error message is created by a dynamic block placed on an IP address by our system. Dynamic blocks are placed when the IP’s statistics break our threshold. These are automated blocks that are removed by the system within 24 hours once the complaints are again below the threshold.
554 RLY:B2
- This error message indicates that a hard block has been placed against your IP address due to poor IP reputation. Resolution will require opening a support request once the IP reputation can be improved.
421 RLY:B3
- The IP address you are sending from has been temporarily rate limited due to poor reputation.
554 RLY:BL
- This error message indicates that a hard block has been placed against your IP address due to poor IP reputation. Resolution will require opening a support request once the IP reputation can be improved.
554 RLY:BD
- This error message indicates that a hard block has been placed against your email because it has triggered too many anti-spam flags. This block is not against the IP. It targets specific types of email.
421 RLY:CH
- A computer, or computers, on your network may be compromised and sending mail that matches the signature of known spam. Before opening a support request, ensure you have a fully qualified domain name, get approved for a complaint Feedback Loop, scan your system for compromises and secure any issues.
554 RLY:CH
- A computer, or computers, on your network may be compromised and sending mail that matches the signature of known spam. Before opening a support request, ensure you have a fully qualified domain name, get approved for a complaint Feedback Loop, scan your system for compromises and secure any issues.
554 RLY:IR
- The reverse DNS of your IP Address is typical of a dynamic/residential IP Address and has a high percentage of invalid recipient attempts. Before opening a support request, ensure you have a fully qualified domain name, get approved for a complaint Feedback Loop, scan your system for compromises and secure any issues.
554 RLY:SN
- This error indicates you are sending email using a disallowed AOL.com Username as your FROM or REPLY-TO address, or as one of AOL’s affiliates from an unauthorized IP address. Example: Billing@aol.com
DYN BLOCKS
421 DYN:T1
- The IP address you are sending from has been temporarily rate limited because it is not Whitelisted, unexpected increase in volume, or poor IP reputation.
421 DYN:T2
- The IP address you are sending from has been asked to delay email delivery to AOL members due to a temporary issue with our mail system. This will be corrected by AOL and no changes should be necessary on your part. If the issue persists, feel free to open a support request with our postmasters.
CON BLOCKS
554 CON:B1
- The IP address has been blocked due to a spike in recent complaints, poor reputation or policy reasons. Please visit our Guidelines and best practices sections for more information on our Technical and policy requirements.
421 CON:B1
- The IP address has been tempfailed due to a spike in recent complaints, poor reputation or policy reasons. Please visit our Guidelines and best practices sections for more information on our Technical and policy requirements.
DMARC BLOCKS
554 DMARC:AOL
- This message failed DMARC Evaluation for an AOL Managed Domain. For more information please visit AOL Mail updates DMARC policy to REJECT.
554 DMARC:F1
- This message failed DMARC Evaluation and is being refused due to the policy provided by the From domain.
554 DMARC:F2
- This message failed DMARC Evaluation because neither DKIM or SPF aligned with the policy provided by the From domain.
554 DMARC:SD
- This message failed DMARC Evaluation because SPF was unaligned and DKIM passed in relaxed mode, however the policy provided by the From domain required strict alignment.
554 DMARC:SP
- This message failed DMARC Evaluation because DKIM and SPF passed in relaxed mode, however the policy provided by the From domain required strict alignment.
554 DMARC:SS
- This message failed DMARC Evaluation because DKIM was unaligned and SPF passed in relaxed mode, however the policy provided by the From domain required strict alignment.
554 DMARC:TE
- This message failed DMARC Evaluation due to an error validating your SPF record, please retry the message.
MFF BLOCKS
421 MFF:DT
- This mail appears to be from the future. Check the clocks on your DKIM signing host(s) and try again later.
421 MFF:MT
- This mail appears to be from the future. Check the clocks on your MTA(s) and try again later.
OTHER ERRORS
An error message from AOL’s email delivery subsystem (mailer-daemon@aol.com) indicates that there was a problem in delivering your message to its destination. When you receive an error from our mail system, your message will be returned to you along with an outline of the mail delivery problem. Due to technological and security limitations, some of the listed error messages may be sent in a bounce message and not during the mail transaction process.
Here are some common errors:
521 Recipient address rejected
This error indicates that the AOL member email address no longer exists or the address is misspelled.
AOL will not accept delivery of this message
This is a permanent bounce due to:
- RFC2822 From domain does not match the rDNS of sending server.
- RFC 2822 FROM address does not have an A record and is not a valid domain.
- IP has a poor reputation and mail is sent to multiple recipients.
- There are multiple From address in the mail headers and the IP reputation is poor.
ESMTP Not accepting connections/Service unavailable:
This is a permanent bounce due to but not limited to below reasons:
- IP reputation is poor and recent spike in mail volume
- IP is not part of AOL Whitelist
550 “Username” Is Not Accepting Mail From This Sender
This error indicates that the AOL member has configured their account, possibly inadvertently, to only accept mail from certain addresses and/or domains. The member will have to change their mail settings in order to receive mail from you. AOL Postmasters cannot override these settings. We respect our member’s privacy and their ability to control their own inbox. AOL Postmasters cannot forward the mail for you. AOL members that have set this rule accidentally can view instructions on how to change the setting, or contact AOL Member Services
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