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Delivery has failed: 550 5.6.0 CAT.InvalidContent.Exception: InvalidCharsetException, Character set name (UNKNOWN) is invalid or not installed. RRS feed

  • Question

  • Hello All,

    We have Exchange 2010 SP1 with Update Rollup 5 environment running on Windows Server 2008 R2 SP1 and Hotfixes.
    Some mails sent by one of our customers cause delivery failure in our Exchange 2010 system.

    According to the delivery report it has unsupported charset in the subject field:
    The e-mail system had a problem processing this message.
    550 5.6.0 CAT.InvalidContent.Exception: InvalidCharsetException, Character set name (UNKNOWN) is invalid or not installed.; cannot handle content of message with InternalId 49856, InternetMessageId…

    I found that this charset causes trouble to Exchange: “=?UNKNOWN?Q?Els=F5?=”

    This failure also appears when I send an empty mail with this subject.
    Does anybody have idea about how to solve this problem?

    Thank you for your help and support in advance.

    Wednesday, October 26, 2011 9:25 AM

All replies

  • Hi

    I recommend you to check the article below to see if it is the supported character.

    Supported Character Sets for Remote Domain Configuration

    http://technet.microsoft.com/en-us/library/aa998600.aspx

    Besides, please try to post the detail NDR message here including all the message headers. If possible, we may remove the relevant header via transport rules.

    Xiu

    Monday, October 31, 2011 6:54 AM
  • I am having similar issues with a few servers. It appears to be either an invalid character or characters or a bare line feed issue.

    I have set the receive connector to reject messages with bare line feeds, but it doesn't seem to fix the issue.

    Do you have same examples of how you would remove the relevant header by using a transport rule?

    Here is an example of one of the messages in the Queue:

     

    Identity: ServerName\Submission\45020726
    Subject: Undeliverable: =?UNKNOWN?Q?Stylists=92?= top PARTY LOOKS
    Internet Message ID: <3fda64fe-a5db-4fd8-a3a6-74798fc3fff8@journal.report.generator>
    From Address: <>
    Status: Retry
    Size (KB): 38
    Message Source Name: SMTP:Default ServerName
    Source IP: 10.10.10.192
    SCL: 0
    Date Received: 11/4/2011 4:07:05 AM
    Expiration Time:
    Last Error: 400 4.4.7 The server responded with: 550 5.6.0 CAT.InvalidContent.Exception: InvalidCharsetException, Character set name (UNKNOWN) is invalid or not installed.; cannot handle content of message with InternalId 45020726, InternetMessageId <3fda64fe-a5db-4fd8-a3a6-74798fc3fff8@journal.report.generator>.. The failure was replaced by a retry response because the message was marked for retry if rejected.
    Queue ID: ServerName\Submission
    Recipients:  Company.dom@jexch.Company.OtherName.net


    Russ Kaufmann, MVP, MCSE, MCT, MCITP, MCTS and other stuff http://infrastructurehelp.wordpress.com

    Friday, November 4, 2011 5:32 PM
  • Hello,

    I've then same issue, but I cannot find a solution...

    Any updates?

     

    Regards,

     

    Pedro

    Monday, January 16, 2012 12:41 PM
  • Hello laszlo39

    this might help: http://support.microsoft.com/kb/2536702

    • Proposed as answer by pvelasco Tuesday, January 17, 2012 12:23 PM
    Tuesday, January 17, 2012 12:23 PM