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Outlook 2013 - Error message "550 Request failed; Mailbox unavailable" RRS feed

  • Question

  • Hello,

    I have been using Outlook 2013 for a while without problems but recently I have started having issues when emailing.

    I frequently send emails for my boss and have the replies directed back to his email. I have also tried changing "from" to his email address so that it looks like it comes directly from him.

    Recently, when I try to do either of these actions I get the email back with the message:  550 Request failed; Mailbox unavailable.

    I have no issues when I leave my email address as the "from", or have the replies just come back to me.

    Any suggestions? Thanks in advance!

    Tuesday, October 15, 2019 6:05 PM

All replies

  • Hi,

    I tested in my environment (Outlook 2013) and cannot reproduce your issue.

    >> I have been using Outlook 2013 for a while without problems but recently I have started having issues when emailing.

    What specific operations did you do before this problem occurred (which may cause this issue)? 

    What's the version of your Outlook 2013?(File > Office Account > About Outlook) Please make sure you have the latest updates installed.

    In this situation, please try leaving your email adress as the "from" and have the replies directly back to his email to see if the issue shows. Besides, to check whether this is a client issue or a server issue, please try exiting Outlook desktop client and see if the issue can be reproduced on the web mail. Or just configure your email account on another computer(Outlook) and see if there is any difference.

    If this is a server issue, it is suggested to remove and re-add the permission of your boss' email account and test again.

    If this is a client  issue, please try the suggestions below:

    1. Starting your Outlook in online mode and see if ther issue persists.(File > Account Settings > Double click your account > Uncheck "Use Cachedd Exchange Mode to download email to an Outlook data file". Restart your Outlook.

    2. There could be some add-ins in your Outlook client that cause this issue, so it is suggested to start your Outlook in safe mode (Press Win + R, type “outlook /safe”, press Enter.) and see if the issue continues.
    3. Besides, it is also suggested to create and use a new Outlook profile via Control Panel > Mail > Show profile and see if there is any difference.
    4. Then if the suggestions above don't work, repair your Office installation or just uninstall and re-install your Office.


    Hope this can be helpful.

    Regards,

    Aidan Wang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Wednesday, October 16, 2019 3:22 AM
  • Hi,

    Have you got the issue fixed?

    I'm writing to see if the reply above is helpful to you. If yes, would you mind helping mark the reply as answer? So that others who might have a similar question can benefit from your thread? Thanks for your understanding and support.

    Regards, 

    Aidan Wang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.


    Thursday, October 17, 2019 8:10 AM