Email bounce error decoder

Find your exact error below, or paste the whole bounce message and we will find the page.

Gmail

• 550 5.1.1 The email account that you tried to reach does not exist
• 550 5.7.1 This message is likely unsolicited email
• 550 5.7.1 This message does not meet IPv6 sending guidelines regarding PTR records and authentication
• 421 4.7.28 Gmail has detected an unusual rate of email originating from your IP address [ip-address]
• 552 5.2.2 The recipient's inbox is out of storage space and inactive
• 552 5.7.0 This message was blocked because its content presents a potential security issue
• 550 5.7.26 Unauthenticated email from [domain] is not accepted due to domain's DMARC policy
• 421 4.7.28 Gmail has detected an unusual rate of unsolicited email originating from your SPF domain [domain]
• 550 5.4.5 Daily user sending limit exceeded
• 550 5.7.25 This message was blocked because the sending IP address doesn't have a PTR record, or the forwarding DNS entry doesn't reference the sending IP address
• 550 5.7.26 This email has been blocked because the sender is unauthenticated
• 550 5.7.27 This message was blocked because it didn’t pass SPF authentication
• 550 5.7.30 This message was blocked because it didn’t pass DKIM authentication
• 550 5.7.40 Your message was blocked because the sending domain doesn’t have a DMARC record or the DMARC record doesn’t specify a DMARC policy
• 550 5.7.29 This message was blocked because it wasn’t sent over a TLS connection
• 550 5.7.24 The SPF record of the sending domain has one or more suspicious entries
• 550 5.7.26 The (E)MAIL FROM domain has an SPF record with a hard fail policy (-all) but it fails to pass SPF checks
• 553 5.1.2 We weren’t able to find the recipient domain
• 554 5.4.6 Message exceeded 50 hops, this may indicate an email loop

Microsoft 365 / Outlook

• 550 5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient not found by SMTP address lookup
• 550 5.7.509 Access denied, sending domain [sender domain] does not pass DMARC verification and has a DMARC policy of reject
• 550 5.7.708 Access denied, traffic not accepted from this IP
• 550 5.7.606-649 Access denied, banned sending IP [IP address]
• 550 5.4.1 Recipient address rejected: Access denied
• 550 5.7.133 RESOLVER.RST.SenderNotAuthenticatedForGroup
• 550 5.7.750 Service unavailable. Client blocked from sending from unregistered domains
• 5.4.14 Hop count exceeded - possible mail loop ATTR34
• 5.7.1 Unable to relay
• 5.7.64 TenantAttribution; Relay Access Denied
• 5.7.57 Client was not authenticated to send anonymous mail during MAIL FROM
• 5.7.511 Access denied, banned sender
• 5.1.8 Access denied, bad outbound sender
• 4.4.7 Message expired
• 5.7.12 Sender was not authenticated by organization

Yahoo / AOL

• 554 5.7.9 Message not accepted for policy reasons
• 554 delivery error: dd This user doesn't have a yahoo.com account

Generic SMTP

• 550 5.1.1 Recipient address rejected: User unknown
• 554 5.7.1 Relay access denied
• 550 5.7.23 SPF validation failed
• 450 4.7.1 Greylisted, see http://postgrey.schweikert.ch/help/example.com.html
• 452 4.2.2 Mailbox full
• 552 5.3.4 Message size exceeds fixed maximum message size
• 554 5.7.1 Service unavailable; Client host [IP address] blocked using zen.spamhaus.org
• 450 4.1.8 Sender address rejected: Domain not found
• 535 5.7.8 Authentication credentials invalid