| Reply Code |
Status Code |
Error Message : Eg |
Explanation |
| 550 |
5.5.1 |
550 5.5.1 Protocol error |
Error message indicating that there is a problem with the way
the
email is being sent, usually related to the protocol commands
or
their sequence.
|
| 550 |
5.1.8 |
550 5.1.8 <user@example.org>: Sender address rejected:
Domain
not found
|
Email rejected as no DNS MX and no DNS A record for the sender
domain.
These records specify the mail servers responsible for receiving
emails on behalf of the sender domain.
If an email cannot be delivered, a bounce message is sent back
to
the sender. Without proper MX and A records, the sender domain
cannot
receive these bounce messages, making it difficult to manage
and
rectify email delivery issues.
|
| 550 |
5.7.27 |
550 5.7.27 <user@example.org>: Sender address rejected: Domain example.org does not accept mail (nullMX)
|
Email rejected as a malformed MX record such as a record with
a zero-length
MX hostname found for the sender domain
|
| 550 |
5.1.1 |
550 5.1.1 <user@example.com>: Recipient address rejected:
User
unknown in virtual mailbox table
|
Recipient email address does not exist |
| 550 |
5.1.1 |
550 5.1.1 <$UserEmailAddress>: Recipient address rejected:
User unknown in local recipient table
|
Recipient email address does not exist |
| 554 |
5.7.1 |
554 5.7.1 <user@example.com>: Relay access denied; |
Recipient email address does not exist |
| 552 |
5.2.2 |
552 5.2.2 user@example.com: Recipient address rejected: Quota
exceeded
(mailbox for user is full)
|
Titan enforces disk quotas to ensure that users do not exceed
their
allocated storage space
|
| 554 |
5.7.1 |
554 5.7.1 Service unavailable; Client host [<ip>] blocked
using
b.barracudacentral.org;
|
IP address is found on an RBL, Titan rejected the email from
that
suspicious IP
|
| 554 |
5.7.1 |
554 5.7.1 command rejected |
IP address is suspicious, Titan rejected the email from that
suspicious
IP
|
| 550 |
5.7.1 |
550 5.7.1 <user@example.com>: Recipient address rejected:
Message
rejected due to: SPF fail - not authorized.
|
SPF Hard failure : The SPF record for the domain specifies a
set
of IP addresses or domains that are allowed to send emails on
behalf
of that domain. If the IP address of the sending mail server
is not
listed in the SPF record, and the SPF record explicitly indicates
that the IP address is not authorized (e.g., through the "-all"
mechanism),
the receiving mail server will consider the email as a hard failure.
|
| 450 |
4.2.0 |
450 4.2.0 <user@example.com>: Recipient address rejected:
greylisted
: please retry after sometime;
|
When an email is received from a suspicious IP address (often
due
to issues with reverse DNS), the server temporarily defers the
message.
The sending mail server is expected to hold the email for a short
period before attempting to resend it. Subsequent retries from
the
sending server will then be accepted.
|
|
550
|
5.4.7 |
550 5.4.7 <user@example.com>: Recipient address rejected: Recipients Domain Hourly Quota Exceeded
|
Ratelimit exceeded
https://support.titan.email/hc/en-us/articles/360038836914-How-many-emails-can-I-send-and-receive?utm_campaign=Titan+Support&utm_source=support-email
|
|
550
|
5.4.7 |
550 5.4.7 <user@example.com>: Recipient address rejected:
Recipients
Domain Daily Quota Exceeded
|
Ratelimit exceeded
https://support.titan.email/hc/en-us/articles/360038836914-How-many-emails-can-I-send-and-receive?utm_campaign=Titan+Support&utm_source=support-email
|
|
550
|
5.4.6 |
550 5.4.6 <user@example.com>: Recipient address rejected:
Recipient
Quota Exceeded;
|
Ratelimit exceeded
https://support.titan.email/hc/en-us/articles/360038836914-How-many-emails-can-I-send-and-receive?utm_campaign=Titan+Support&utm_source=support-email
|
|
550
|
5.4.6 |
550 5.4.6 <user@example.com>: Recipient address rejected:
Mailbox
Does Not Exist : Domains Hourly Quota Exceeded;
|
Ratelimit exceeded
https://support.titan.email/hc/en-us/articles/360038836914-How-many-emails-can-I-send-and-receive?utm_campaign=Titan+Support&utm_source=support-email
|
|
550
|
5.4.6 |
550 5.4.6 <user@example.com>: Recipient address rejected:
Mailbox
Does Not Exist : Domains Daily Quota Exceeded;
|
Ratelimit exceeded
https://support.titan.email/hc/en-us/articles/360038836914-How-many-emails-can-I-send-and-receive?utm_campaign=Titan+Support&utm_source=support-email
|
| 550 |
5.7.1 |
550 5.7.1 message content rejected |
Ratelimit exceeded
https://support.titan.email/hc/en-us/articles/360038836914-How-many-emails-can-I-send-and-receive?utm_campaign=Titan+Support&utm_source=support-email
|
| 550 |
5.2.1 |
550 5.2.1 <user@example.com>: Recipient address rejected:
Incoming
suspended due to abuse
|
This domain is suspended due to suspicious activity , currently
incoming
emails are not getting accepted
|
| 550 |
5.2.1 |
550 5.2.1
<user@example.com>
: Recipient address rejected: Incoming temporarily suspended
due to partner migration
|
This domain is suspended due to ongoing partner migration, currently
incoming emails are not being accepted.
|
| 550 |
5.7.2 |
550 5.7.2 <ip>: Sender IP rejected: spam rate exceeded
|
Your email was rejected because the sending mail server has been
sending an unusually high volume of spam or suspicious messages.
To protect our users, we block emails from servers that exceed
safe
sending thresholds.
|
| 421 |
4.7.0 |
421 4.7.0
: Sender IP rejected: sending IP has insufficient reputation.
Please retry later.
|
Your email couldn’t be delivered because the sending IP address
doesn’t
yet have sufficient reputation, as it’s new in our system. This
rejection
is temporary—please try sending your email again later.
|
| 550 |
5.7.1 |
550 5.7.1
: Recipient address rejected: Message rejected, sender domain
does not pass spf requirements
|
The sending IP address used to send email is not authorized in
your
SPF record or either your spf record is incorrect. If this email
is legitimate, you should update your SPF configuration to include
the correct sending sources.
|
| 550 |
5.7.1 |
550 5.7.1 Sending temporarily restricted due to observed sending patterns. Please retry later. |
The sending domain has exceeded its permitted message rate. This limit is applied based on the domain's sending reputation score, domains with very low reputation scores are subject to strict hourly and daily sending thresholds.
|