Why do I get error code 0x8004210b when using Outlook?

Question

Why do I get error code 0x8004210b when using Outlook?

Answer

Outlook error code 0x8004210b occurs when Outlook is having issues connecting to a remote server and a timeout occurs. 

There a few reasons for this to happen, mostly related to the client-side of the transaction:

• Corrupt Outlook installation
• Windows Registry issues with Outlook
• Corruption with OutlLook application files due to malware
• Missing Outlook files
• Antivirus/Firewall software blocking Outlook

The following site provides detailed information about the issue and applicable workarounds to fix the issue: 

https://www.outlookfaq.com/errors/fix-0x8004210b-error-message-in-microsoft/