Encountering error codes can be frustrating and time-consuming. Understanding these codes and their meanings is crucial for effective troubleshooting. This article will provide you with a comprehensive list of email error codes, categorized by their respective code ranges. By familiarizing yourself with these codes, you will be better equipped to promptly identify and resolve email-related issues.
200 Codes:
211 – System status/system help reply:
The 211 code signifies a successful connection to the email server. It provides information about the server’s status and can be helpful for diagnostic purposes.
214 – Help message:
When encountering this code, the server offers the client assistance or information. It may provide details about available commands or other relevant support.
220 – Domain service ready:
This code indicates that the domain service is ready to accept incoming email messages. It confirms that the server is operational and prepared to handle email transactions.
221 – Domain service closing transmission channel:
When the server sends the 221 code, it signifies the end of the email transmission channel. This code is typically used when the server is about to close the connection.
250 – Requested mail action completed and OK:
A 250 code indicates that the requested mail action has been successfully executed. It confirms that the email has been sent or received without any issues.
251 – Not Local User, forward email to forward path:
When encountering this code, the server informs the sender that the recipient is not a local user. Instead, it advises the sender to forward the email to a specific forward path.
252 – Cannot Verify user, will attempt delivery later:
In cases where the server cannot verify the user’s existence, it may return the 252 code. This code suggests that the server will attempt to deliver the email at a later time.
253 – Pending messages for node started:
When a server encounters the 253 code, it indicates that there are pending messages waiting to be sent to a specific node. This code serves as an acknowledgment of the pending messages.
300 Codes:
354 – Start mail input; end with “.”:
The 354 code is used to initiate the mail input process. It prompts the client to provide the email content, which should end with a period (.) to indicate the completion of the message.
355 – Octet-offset is the transaction offset:
When the server returns the 355 code, it specifies the transaction offset in octets. This information can be helpful for tracking and managing email transactions.
400 Codes:
421 – Domain service not available, closing transmission channel:
Encountering the 421 code indicates that the domain service is temporarily unavailable. The server closes the transmission channel, preventing further communication.
432 – Domain service not available, closing transmission channel:
Similar to the 421 code, the 432 code signifies that the domain service is currently unavailable. As a result, the server terminates the transmission channel.
450 – Requested mail action not taken: mailbox unavailable. Request refused:
When the server returns the 450 code, it indicates that the requested mail action cannot be completed because the recipient’s mailbox is unavailable or the request has been refused.
451 – Requested action aborted: local error in processing. Request is unable to be processed; try again:
The 451 code suggests that the requested action has been aborted due to a local error during processing. It advises the sender to try again later.
452 – Requested action not taken: insufficient system storage:
Encountering the 452 code signifies that the requested action cannot be completed due to insufficient system storage. It indicates that the server lacks the necessary space to process the email.
453 – No mail:
When the server returns the 453 code, it indicates that there is no mail available for the recipient. This code suggests that the recipient’s mailbox is empty.
454 – TLS is not available due to temporary reasons. Encryption required for the requested authentication mechanism:
The 454 code informs the sender that Transport Layer Security (TLS) is temporarily unavailable. It indicates that encryption is required for the requested authentication mechanism.
458 – Unable to queue messages for node:
Encountering the 458 code suggests that the server is unable to queue messages for a specific node. This code may indicate a temporary issue with the server’s message queue.
459 – Node not allowed: reason:
When the server returns the 459 code, it signifies that the specified node is not allowed. The accompanying reason provides further details about the restriction.
500 Codes:
500 – Syntax error, command unrecognized:
The 500 code indicates a syntax error, suggesting that the server does not recognize the command provided by the client. This code often occurs when the command has a typographical or formatting error.
501 – Syntax error in parameters or arguments:
Encountering the 501 code suggests a syntax error in the parameters or arguments provided with the command. This code indicates that the server cannot interpret the command due to incorrect formatting.
502 – Command not implemented:
When the server returns the 502 code, it signifies that the requested command is not implemented or supported. This code suggests that the server does not recognize or support the specific command.
503 – Bad sequence of commands:
The 503 code indicates that the commands provided by the client are in an incorrect sequence. This code suggests that the client needs to reorder or modify their commands to proceed successfully.
504 – Command parameter not implemented:
Encountering the 504 code suggests that the requested command parameter is not implemented or supported by the server. This code indicates that the server cannot fulfill the request due to the unsupported parameter.
510 – Check the recipient address:
When the server returns the 510 code, it advises the sender to check the recipient’s email address. This code suggests that there may be an issue with the recipient’s address, such as a typo or an invalid domain.
512 – Domain cannot be found. Unknown host:
Encountering the 512 code indicates that the server cannot find the specified domain. This code suggests that the host or domain name provided is unknown or does not exist.
515 – Destination mailbox address invalid:
The 515 code suggests that the destination mailbox address is invalid. This code indicates that the recipient’s email address is either misspelled or does not exist.
517 – Problem with sender’s mail attribute, check properties:
When the server returns the 517 code, it suggests that there is a problem with the sender’s mail attribute. This code advises the sender to check the properties or settings associated with their email account.
521 – Domain does not accept mail:
Encountering the 521 code indicates that the specified domain does not accept incoming mail. This code suggests that the server responsible for the domain has configured it to reject incoming messages.
522 – Recipient has exceeded mailbox limit:
The 522 code suggests that the recipient has exceeded their mailbox limit. This code indicates that the recipient’s mailbox is full and cannot accept any more messages.
523 – Server limit exceeded. Message too large:
When the server returns the 523 code, it signifies that the message size exceeds the server’s limit. This code suggests that the email message is too large to be processed or delivered.
530 – Access Denied. Authentication required:
Encountering the 530 code indicates that access to the server is denied without proper authentication. This code suggests that the client needs to provide valid credentials to proceed.
531 – Mail system Full:
The 531 code suggests that the mail system is currently full and cannot accept any more messages. This code indicates that the server has reached its storage capacity.
533 – Remote server has insufficient disk space to hold email:
When the server returns the 533 code, it suggests that the remote server does not have sufficient disk space to store the email. This code indicates that the recipient’s server is running low on storage capacity.
534 – Authentication mechanism is too weak. Message too big:
Encountering the 534 code indicates that the authentication mechanism used is considered too weak by the server. Additionally, it suggests that the email message is too large to be processed with the current authentication mechanism.
535 – Multiple servers using the same IP. Required Authentication:
The 535 code suggests that multiple servers are using the same IP address. As a security measure, the server requires authentication to ensure the legitimacy of the sender.
538 – Encryption required for requested authentication mechanism:
When the server returns the 538 code, it indicates that encryption is required for the requested authentication mechanism. This code suggests that the client needs to establish a secure connection to proceed.
540 – Email address has no DNS Server:
Encountering the 540 code suggests that the email address provided does not have a DNS (Domain Name System) server associated with it. This code indicates that the email address is invalid or misconfigured.
541 – No response from host:
The 541 code indicates that there is no response from the host. This code suggests that the server or recipient’s system is unresponsive or experiencing connectivity issues.
542 – Bad Connection:
Encountering the 542 code suggests that there is a bad connection between the client and the server. This code indicates that the communication between the two entities is disrupted or unstable.
543 – Routing server failure. No available route:
When the server returns the 543 code, it signifies a routing server failure. This code suggests that there is no available route to deliver the email, possibly due to a network or configuration issue.
546 – Email looping:
The 546 code indicates that an email loop has occurred. This code suggests that the email is being continuously forwarded or bounced between servers, resulting in an infinite loop.
547 – Delivery time-out:
Encountering the 547 code suggests that the delivery of the email has timed out. This code indicates that the server has been unable to deliver the email within the specified time frame.
550 – Requested action not taken: mailbox unavailable:
When the server returns the 550 code, it suggests that the requested action cannot be taken because the recipient’s mailbox is unavailable. This code often occurs when the recipient’s email account has been deactivated or deleted.
551 – User not local; please try forward path:
The 551 code indicates that the user is not local to the server. It advises the sender to try the forward path, suggesting that the email should be forwarded to an alternative address.
552 – Requested mail action aborted: exceeded storage allocation:
Encountering the 552 code suggests that the requested mail action has been aborted due to the recipient exceeding their storage allocation. This code indicates that the recipient’s mailbox is full and cannot accept any more messages.
553 – Requested action not taken: mailbox name not allowed:
The 553 code suggests that the requested action cannot be taken because the mailbox name is not allowed. This code often occurs when the recipient’s email address violates certain naming conventions or restrictions.
554 – Transaction failed:
When the server returns the 554 code, it signifies that the transaction has failed. This code suggests that there is an issue preventing the successful completion of the email transmission.
Complete list email error codes
You can effectively troubleshoot and resolve email-related issues by familiarizing yourself with these email error codes. Understanding the meaning behind these codes allows you to identify the root cause of the problem and take appropriate action. Remember, error codes are not roadblocks but signposts guiding you toward a solution.
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