This article describes the Outlook Error Code 0x8004210B. It is Microsoft Outlook Error. This Error restricts your ability to send/receive emails on your Outlook email address successfully. This error is quite common and is faced with many Microsoft Outlook users.
Disclaimers: Fixing an error on Outlook deals with your emails and attachments. Please backup your emails and it’s folders before you proceed. If you are not sure about the procedure, contact the technician for the support.