Error 0x800CCC79 - Recipient not authorised / Unknown local user
This is a common error that can be caused by a number of factors. You can usually resolve this fault without having to seek assistance.
Cause 1, Mail Relay:
The most common cause for these errors, is when sending mail through the BT Broadband mail servers using a 3rd party domain name that has not been registered for mail relay.
Mail relaying occurs when email is sent through a set of mail servers. Sending email through the BT Broadband mail servers is perfectly normal as long as the sender of the message is using a BT account. If the sender of the email is not a BT Broadband user, this is called third-party mail relaying and this is how most Spam mail on the Internet is sent. In an attempt to reduce the amount of spam emails sent through the BT Broadband mail servers, we require that mail relay is setup.
If you are using a domain name that is not hosted with BT Broadband, this will not automatically be set up for mail relay. Therefore you will have to manually request that your domain name is set up for mail relay on the BT Broadband mail servers. See How can I set up mail relay?for full details of how to set this up.
Cause 2, Recipient's mailbox unreachable:
Another cause for this error is when the recipient’s mailbox is unreachable.
This would mean that the person you are trying to send an email to has a problem with their email account. Basically, their email account is either full or not in operation.
If this were the case, we would recommend contacting the person you are trying to email via a different method and asking them to check that their email account is working correctly.
Cause 3, SMTP Authentication:
This error can also occur if you are using a mail client (Outlook Express, Entourage etc) and do not have SMTP authentication setup.
SMTP authentication is an additional option setup on mail clients that helps prevent other members of an ISP from sending Spam to our customers as well as others.
In order to send mail through the BT Broadband servers, you will have to ensure that you have SMTP authentication enabled (if using a mail client).
If you do not know how to setup SMTP authentication, below are 2 links that give full walkthroughs for both PC and MAC users.
Cause 4, Sending from an invalid email address:
If you are trying to send email from an invalid email address this error will be displayed. If the address you are sending from does not appear to be valid, our server will not send the email. An email account would become invalid if any of the following occurs:
- The account is suspended
- The mailbox is over the quota limit
- The account has been deleted
- The address you are sending from is spelled incorrectly
- It is at least 24 hours since the email address was created
If you have created a new email address, please note that it may take our system up to 24 hours to activate this. This applies to whether you have created a new email account (yourname@btconnect.com) or an email alias (yourname@yourdomain.co.uk) on an active email address.
Cause 5, Webmail:
If you are using the BT Broadband Webmail service, you can still receive these errors.
This can happen when logging into the Webmail section of the btconnect.com website with an incorrect set of username and password details. Also, you would have to ensure you are only using the first part of the email address.
For example, if your email address is yourname@btconnect.com, you only need to enter ‘yourname’. When you send your email, @btconnect.com will automatically be added to the address.
If you still need help and want to call or chat online please contact us.
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