SMTP Error Code 550

The transaction failed permanently. The server will not try to send the message again. This is used as a general error code, so there are many reasons why you could be seeing it.

It’s common for email service providers to add a status code (5.1.1) after the SMTP reply code (smtp;550) for additional categorization of the issue.

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Email service providers

AppleAll Apple codes →

smtp;550 5.1.1 <example@icloud.com>: user does not exist

smtp;550 5.7.1 [CS01] Message rejected due to local policy. Please visit https://support.apple.com/en-us/HT204137

smtp;550 5.7.1 Your message was rejected due to example.com’s DMARC policy. See https://support.apple.com/en-us/HT204137 for info

High severity

smtp;550 5.7.1 Your email was rejected due to having a domain present in the Spamhaus DBL -- see https://www.spamhaus.org/dbl/

Critical severity

AT&TAll AT&T codes →

smtp;550 5.2.1 <EXAMPLE@PRODIGY.NET>... Addressee unknown, relay=[x.xx.xx.xx]

smtp;550 5.2.1 <example@prodigy.net>... blank mailhost - invalid address, relay=[x.xx.xx.xx]

smtp;550 5.7.1 Connections not accepted from servers without a valid sender domain. ## Fix reverse DNS for x.xx.xx.xx

High severity

ComcastAll Comcast codes →

smtp;550 5.1.1 Not our Customer

Low severity

smtp;550 5.1.1 <example@comcast.net> recipient mailbox unallocated

smtp;550 5.2.0 Message rejected due to DMARC. Please see http://postmaster.comcast.net/smtp-error-codes.php#DM000001

High severity

smtp;550 5.2.0 <example@comcast.net> - Recipient unavailable

FreeAll Free codes →

smtp;550 spam detected

Medium severity

smtp;550 5.2.2 user quota exceeded

smtp;550 5.2.1 This mailbox has been blocked due to inactivity

Low severity

smtp;550 virus detected

Critical severity

GMXAll GMX codes →

smtp;550 Requested action not taken: mailbox unavailable

Requested action not taken: mailbox unavailable Reject due to policy restrictions.

GoogleAll Google codes →

smtp;550 5.1.1 The email account that you tried to reach does not exist. Please try double-checking the recipient's email address for typos or unnecessary spaces. Learn more at https://support.google.com/mail/?p=NoSuchUser - gsmtp

smtp;550 5.2.1 The email account that you tried to reach is disabled. Learn more at https://support.google.com/mail/?p=DisabledUser - gsmtp

smtp;550 5.2.1 The user you are trying to contact is receiving mail at a rate that prevents additional messages from being delivered. For more information, please visit https://support.google.com/mail/?p=ReceivingRatePerm - gsmtp

High severity

smtp;550 5.7.1 [x.xx.xx.xx] Our system has detected that this message is likely suspicious due to the very low reputation of the sending domain. To best protect our users from spam, the message has been blocked. Please visit https://support.google.com/mail/answer/188131 for more information. - gsmtp

Critical severity

smtp;550 5.7.1 [x.xx.xx.xx] Our system has detected that this message is likely unsolicited mail. To reduce the amount of spam sent to Gmail, this message has been blocked. Please visit https://support.google.com/mail/?p=UnsolicitedMessageError for more information. - gsmtp

Critical severity

smtp;550 5.7.1 Unauthenticated email from example.com is not accepted due to domain's DMARC policy. Please contact the administrator of example.com domain if this was a legitimate mail. Please visit https://support.google.com/mail/answer/2451690 to learn about the DMARC initiative. - gsmtp

High severity

smtp;550 5.7.1 [x.xx.xx.xx 14] Messages missing a valid address in From: header, or having no From: header, are not accepted. - gsmtp

HeyAll Hey codes →

smtp;550 5.1.1 <example@hey.com>: Recipient address rejected: User unknown

Low severity

HostpointAll Hostpoint codes →

smtp;550-SPF-check failed: 550 example.com doesn't allow sending mails from xx.xx.xx.xx (in reply to MAIL FROM command)

ImprovMXAll ImprovMX codes →

smtp;550 5.7.1 Message considered as SPAM

InfomaniakAll Infomaniak codes →

smtp;550 5.7.1 rejected by DMARC policy for example.com (in reply to end of DATA command),

Mail.ruAll Mail.ru codes →

smtp;550 Message was not accepted -- invalid mailbox. Local mailbox example@mail.ru is unavailable: account is disabled

Low severity

smtp;550 spam message rejected. Please visit http://help.mail.ru/notspam-support/id?c=7y4ytdHbuOGv3O50NYTwpz1F-TVIpnactxtFPeFQSDYMAAAAaKgAAOX_3hE~ or report details to abuse@corp.mail.ru. Error code: ###. ID: #

High severity

smtp;550 Message was not accepted -- invalid mailbox. Local mailbox example@mail.ru is unavailable: account is disabled

OrangeAll Orange codes →

smtp;550 5.2.0 Mail rejete. Mail rejected. ofr_506 [506]

smtp;550 5.1.1 Adresse d au moins un destinataire invalide. Invalid recipient. OFR_416 [416]

smtp;550 mwinfXXXX ME Adresse IP source bloquee pour incident de spam. Client host blocked for spamming issues. OFR006_102 Ref http://csi.cloudmark.com/reset-request/?ip=xxx.xxx.xxx.xxx [102]

High severity

OutlookAll Outlook codes →

smtp;550 5.5.0 Requested action not taken: mailbox unavailable. [#.eop-nam12.prod.protection.outlook.com]

smtp;550 5.7.1 Service unavailable, MailFrom domain is listed in Spamhaus. To request removal from this list see https://www.spamhaus.org/query/lookup/ (S8002) [#.eop-nam02.prod.protection.outlook.com]

Critical severity

smtp;550 5.7.1 Unfortunately, messages from [x.xx.xx.xx] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [#.eop-nam02.prod.protection.outlook.com]

High severity

smtp;550 5.4.1 All recipient addresses rejected : Access denied [#.eop-nam02.prod.protection.outlook.com]

Medium severity

ProtonMailAll ProtonMail codes →

smtp;550 5.7.1 Rejected by spam filter (in reply to end of DATA command)

QQAll QQ codes →

smtp;550 Mail is rejected by recipients

smtp;550 Mailbox unavailable or access denied

smtp;550 Mailbox not found. http://service.exmail.qq.com/cgi-bin/help?subtype=1&&id=20022&&no=1000728

smtp;550 Mail content denied. http://service.exmail.qq.com/cgi-bin/help?subtype=1&&id=20022&&no=1000726

smtp;550 Sender frequency limited. http://service.exmail.qq.com/cgi-bin/help?subtype=1&&id=20022&&no=1000723

smtp;550 Suspected spam sender.

High severity

smtp;550 DMARC check failed http://service.mail.qq.com/cgi-bin/help?subtype=1&&no=1001508&&id=16.

High severity

RackspaceAll Rackspace codes →

smtp;550 5.1.1 Email address could not be found, or was misspelled (G8)

Web.deAll Web.de codes →

smtp;550 <example@example.com>: Reject due to SPF policy. The originating IP of the message is not permitted by the domain owner

smtp;550 <example@example.com>: Syntax error in parameters or arguments

smtp;550 <example@example.com>: Requested action not taken: mailbox unavailable

smtp;550 <example@example.com>: Bad DNS PTR resource record

smtp;550 <example@example.com>: Reject due to policy restrictions (header based)

smtp;550 <example@example.com>: Reject due to policy restrictions (domain based)

smtp;550 <example@example.com>: Reject due to policy restrictions (IP based)

smtp;550 <example@example.com>: Requested mail action aborted: exceeded storage allocation, Quota exceeded

smtp;550 <example@example.com>: IP address is block listed

smtp;550 <example@example.com>: Invalid DNS MX or A/AAAA resource record

Yahoo IncAll Yahoo Inc codes →

smtp;550 relaying denied for <example@example.com>

YandexAll Yandex codes →

smtp;550 5.7.1 Policy rejection on the target address

smtp;550 5.7.1 No such user!

ZohoAll Zoho codes →

smtp;550 5.7.1 Email rejected per DMARC policy for zoho.com

smtp;550 5.1.1 <example@zoho.com> User unknown

Spam filters services

BarracudaAll Barracuda codes →

smtp;550 cuda_nsu 5.1.1 <email@example.com>... User unknown

Low severity

smtp;550 No such user (email@example.com)

Low severity

smtp;550 Blocked

smtp;550 rejecting spoofed message

High severity

smtp;550 permanent failure for one or more recipients (email@example.com:blocked)

Email Security.cloudAll Email Security.cloud codes →

smtp;550 Invalid recipient <email@example.com> (#5.1.1)

Exchange OnlineAll Exchange Online codes →

smtp;550 5.4.1 [email@example.com]: Recipient address rejected: Access denied [example.com]

smtp;550 5.7.1 Service unavailable, Client host [x.xx.xx.xx] blocked using Spamhaus. To request removal from this list see https://www.spamhaus.org/query/ip/0.0.0.0 (AS16012611)

Critical severity

550 5.7.1 Service unavailable, Helo domain is listed in Spamhaus. To request removal from this list see https://www.spamhaus.org/query/lookup/ (S8001) [#.prod.protection.outlook.com]

Critical severity

smtp;550 5.7.606 Access denied, banned sending IP [x.xx.xx.xx]. To request removal from this list please visit https://sender.office.com/ and follow the directions. For more information please go to http://go.microsoft.com/fwlink/?LinkID=526655 (AS16012609)

Critical severity

FireEyeAll FireEye codes →

smtp;550 5.7.26 <example@example.com>: ETP205 DMARC Failure for domain

MimecastAll Mimecast codes →

smtp;550 Administrative prohibition - envelope blocked - https://community.mimecast.com/docs/DOC-1369#550 [#]

smtp;550 Rejected by header based Anti-Spoofing policy: email@example.com - https://community.mimecast.com/docs/DOC-1369#550 [#]

smtp;550 Rejected by header based manually Blocked Senders: email@example.com - https://community.mimecast.com/docs/DOC-1369#550 [#]

smtp;550 Envelope blocked - User Entry - https://community.mimecast.com/docs/DOC-1369#550 [#]

smtp;550 DMARC Sender Invalid - envelope rejected - https://community.mimecast.com/docs/DOC-1369#550 [#]

High severity

ProofpointAll Proofpoint codes →

smtp;550 5.1.1 <email@example>: Recipient address rejected: User unknown

smtp;550 5.1.1 <email@example.com>: Recipient address rejected: undeliverable address: host example.com[x.xx.xx.xx] said: 550 5.1.1 <email@example.com>: Recipient address rejected: user unknown

smtp;550 5.1.1 User Unknown

smtp;550 5.1.1 - This is not a valid email address. Please verify that you have the correct email address for your recipient.

smtp;550 5.1.8 <sender@example.com>: Sender address rejected: Domain not found (in reply to RCPT TO command)

High severity

smtp;550 5.1.8 Domain of sender address does not exist

High severity

smtp;550 5.5.2 <email@example.com>: Sender address rejected: need fully-qualified address (in reply to RCPT TO command)

High severity

smtp;550 5.7.0 Email rejected per sender's DMARC policy

High severity

smtp;550 5.7.1 <email@example.com>: Recipient address rejected: User email address is marked as invalid.

smtp;550 5.7.1 Relaying denied

smtp;550 5.7.1 Relay access denied

smtp;550 5.7.1 Service unavailable; client [x.xx.xx.xx] blocked using prs.proofpoint.com

High severity

smtp;550 5.7.1 Service unavailable; client [x.xx.xx.xx] blocked using Cloudmark Sender Intelligence (Visit http://csi.cloudmark.com/reset-request/ if you feel this is in error)

High severity

Trend MicroAll Trend Micro codes →

smtp;550 5.7.1 <example@example.com>: Recipient address rejected: ERS-Customized-Block.

Other SMTP codes

Built with

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