Sometimes when sending an email, you may receive a mail delivery failure notification or bounceback and you may wonder to yourself, \u201cwhy am I seeing this?\u201d.<\/p>\n\n\n\n
This guide will cover some of the more common errors and provide an explanation of what might cause the error and any remedial steps you can take.<\/p>\n\n\n\n
Let\u2019s get started\u2026<\/p>\n\n\n\n
<\/a><\/p>\n\n\n\n This is one of the most common error responses when a recipient mail server has rejected delivery of an email. We\u2019ll cover some of the different causes for these errors and the error messages that can accompany the mail delivery failure notifications for 550 errors below:<\/p>\n\n\n\n These errors can be returned if you\u2019ve tried to send an email to an address that doesn\u2019t exist, has a typo or has been deactivated:<\/p>\n\n\n\n These errors can indicate that recipient mail server doesn\u2019t think that it is responsible for routing mail for the domain\/address in question:<\/p>\n\n\n\n These errors can indicate that the mail has been blocked due to spam filter settings on the recipient server, blacklisting of the sending server IP, reputation issues or high volumes of mail originating from the sending server:<\/p>\n\n\n\n SPF records are used to indicate which servers are authorised to send mail for a domain. If an SPF record is misconfigured, or if an attempt to send mail from a server not authorised by the SPF record is made it can result in errors:<\/p>\n\n\n\n If the recipient mailbox doesn\u2019t have enough available space to accept delivery of your message it can result in these errors. Most mail servers will set a maximum file size limit for attached files \u2013 if you\u2019re trying to send an attachment larger than 10MB it can also result in this type of error.<\/p>\n\n\n\n In most cases with 550 errors it will be the responsibility of the recipient to address the problem as it will be out of your control to resolve.<\/p>\n\n\n\n If this error is being returned for a mailbox hosted with LCN, here are some things to check:<\/p>\n\n\n\n <\/a><\/p>\n\n\n\n These errors are returned by the sending server rather than the recipient mail server and usually indicate that your attempt to send an outgoing mail has been blocked.<\/p>\n\n\n\n The cause will depend on the specific error that accompanies it. This could be DNS related such as no MX records<\/a>. It could also mean that you have reached a sending limit for your email or domain name.<\/p>\n\n\n\n <\/a><\/p>\n\n\n\n A 554 error is usually related to reputation leading to being blocked or blacklisted at the recipient\u2019s side. This could be an IP, the domain name or the email address itself. To help avoid this make sure that emails you are sending are not being considered as spam to help make sure your domain and email address reputation stays in good standing.<\/p>\n\n\n\n We have a guide on how to not be considered spam here<\/a>.<\/p>\n\n\n\n When this occurs, you will need to read the error to try and identify the block as it will advise who to contact to resolve the issue. For example, if it is a block implemented by Microsoft it will need to be reported to them to resolve.<\/p>\n\n\n\n <\/a><\/p>\n\n\n\n 551 is commonly an authentication error. This would usually be seen when sending emails from a mail client such as Outlook or Mac Mail or from a mobile device.<\/p>\n\n\n\n This will relate to your outgoing mail server settings likely being incorrect, this could be that you have not set up your outgoing server settings to use authentication or the details are incorrect in some way, this could be a typo in your email address or an incorrect password.<\/p>\n\n\n\n Review your outgoing server settings and make sure they are correct, you can find our settings here<\/a>.<\/p>\n\n\n\n550 Errors<\/h3>\n\n\n\n
550 No Such User Here\n550-5.1.1 The email account that you tried to reach does not exist.\n550 permanent failure for one or more recipients550 Requested action not taken: mailbox unavailable\n550 5.7.1 <example@domain.com>... unknown user\n550 5.4.1 Recipient address rejected: Access denied550 Unrouteable address.<\/example@domain.com><\/pre>\n\n\n\n
Check for any spelling errors in the email address that you\u2019ve sent to and check with the intended recipient to confirm if their email address hasn\u2019t changed.<\/p>\n\n\n\n550 relay not permitted\n550 5.7.1 <example@domain.com>... Relaying denied<\/example@domain.com><\/pre>\n\n\n\n
550 relay not permitted\n550 5.7.1 <example@domain.com>... Relaying denied<\/example@domain.com><\/pre>\n\n\n\n
This could occur when the MX records for a domain are set incorrectly, when there\u2019s a problem with the configuration of the mail server for the domain or if the email hosting for the domain has expired or been suspended.<\/p>\n\n\n\n550 Sender address belongs to a non-trusted organisation \n550 #5.7.1 Your access to submit messages to this e-mail system has been rejected.\n550 The sending IP (xx.xx.xx.xx) is listed on https:\/\/blacklisturl.com\/.<\/pre>\n\n\n\n
550 xx.xx.xx.xx is not allowed to send mail from domain.com.<\/pre>\n\n\n\n
451 Errors<\/h3>\n\n\n\n
554 Errors<\/h3>\n\n\n\n
551 Errors<\/h3>\n\n\n\n