TECH 2U Email Error Codes

This page lists the most common email error codes used by TECH 2U

If you have been referred to this page by an error code we suggest finding the code below and then actioning accordingly.

SMTP Codes (Errors et al.)

SMTP codes consist of three digits, for example, 550, 551, 221, 354, etc. Not all of them mean an error although most people are only interested in those that do. In order to understand how these codes work, you have to know that each digit (the first, the second and the third) have their own meaning.

The first digit tells you if your command was accepted and processed. There are five different values for that:

1. Mail server has accepted the command, but does not yet take any action. A confirmation message is required.

2. Mail server has completed the task successfully without errors.

3. Mail server has understood the request, but requires further information to complete it.

4. Mail server has encountered a temporary failure. If the command is repeated without any change, it might be

completed. Try again, it may help!

5. Mail server has encountered a fatal error. Your request can't be processed.

As you can see, the codes that start with 4 and 5 are the ones that tell you that your message won't be sent until you find and fix the problem.

The second digit tells you more

  0. Syntax error

   1. Information reply (for example to HELP request)

   2. This digit refers to the status of connection

   3. This digit refers to the status of the mail server

   4. Not used

   5. Not used

The third (last) digit of the code tells you the details of mail transferring status.

Error Code Description
421 Service not available, closing transmission channel (This may be a reply to any command if the service knows it must shut down)
450 Requested mail action not taken: mailbox unavailable (E.g., mailbox busy)

Requested action aborted: local error in processing

            Contact TECH 2U Support Desk with the relevant details so we can check.

452 Requested action not taken: insufficient system storage
500 Syntax error, command unrecognized (This may include errors such as command line too long)
501 Syntax error in parameters or arguments
502 Command not implemented
503 Bad sequence of commands
504 Command parameter not implemented

Mailbox disabled

            At this point you need to give up as we have that mailbox turned off. We do not want it to receive emails.


Email not accepted from fake customer names

            This means that a user with a TECH 2U email address / domain is trying to send an email into the TECH 2U system from outside the network. As we would

be expecting that TECH 2U customers would be using the TECH 2U system we therefore take it that anyone using that name is probably faking the name in order

to circumvent our spam filters. Sorry this is not allowed. The message is therefore blocked.

            If you happen to be a TECH 2U customer and for some reason need to send emails from outside the network (friends house, customer office, hotels on

holidays etc) please contact the TECH 2U Support Desk for assistance and instructions on how to do so.

552 Requested mail action aborted: exceeded storage allocation
553 Requested action not taken: mailbox name not allowed (E.g., mailbox syntax incorrect)
554 ERROR:554

We do not accept email sent from this ip address.

            TECH 2U and our customers hate spam.

            At some point in the past the ip address allocated to your email server has been detected as sending spam messages. As a result our system has

blocked all emails coming from that location. These emails may have come from your system (we suggest that you stop sending them or check your system

security in case someone else is doing it without your knowledge) or may have come from that location by a previous user of that internet address. In some

cases a shared email server at an internet service provider may be the culprit.

            In all cases if the spam has stopped (and you are not the spammer) we suggest contacting TECH 2U Support with the time the error message showed and

your full email address. We will then check the logs and if no spam is still coming in we will remove the address from our filters.

Home Page  ::  Contact Us  ::  Make This My Homepage  ::  Filtering Software
TECH 2U - Logo

TECH 2U Relocation Details. - Image ITP July Special Offer - Image Our Place. Meet. Greet. Enjoy. - Image
North Shore Office Supplies Australian Corporate Diaries b2b Networking