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Quick Ways to fix Microsoft outlook Error code 0x8004210B

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Error 0x8004210B is commonly referred to as the “SMTP timeout” error. It typically appears when Outlook fails to establish a connection with the mail server within the designated time. This error can prevent you from sending or receiving emails, causing inconvenience, and affecting your productivity.

Error code 0x8004210b

Possible Causes of Microsoft 365 Error 0x8004210B:

Network Issues:

A weak or unstable internet connection can disrupt the communication between Outlook and the mail server, leading to the error 0x8004210B.

Firewall or Antivirus Interference:

Sometimes, security software such as firewalls or antivirus programs can block Outlook’s access to the mail server, the error 0x8004210B.

Simple Solutions to Resolve Outlook Error Code 0x8004210B:

Check your Internet Connection:

Ensure that your internet connection is stable and functioning correctly. Try accessing other websites or services to verify the reliability of your connection.

Disable Firewall or Antivirus Temporarily:

Temporarily disable your firewall or antivirus software to determine if they are causing the conflict. If the error disappears after disabling them, consider reconfiguring your security software to allow Outlook’s communication.

Verify Server Settings:

Double-check your server settings in Outlook to ensure they are accurate. Ensure that the incoming and outgoing server addresses, ports, and security protocols (such as SSL/TLS) are configured correctly according to your email provider’s instructions.

More Possible Causes of Microsoft outlook Error code 0x8004210B:

Server Configuration Problems:

Incorrect server settings or configuration issues can prevent Outlook from establishing a proper connection with the mail server, resulting in the error message.

Large Email Attachments:

Sending or receiving emails with large attachments can consume more time, increasing the likelihood of a timeout error 0x8004210B.

More Quick Solutions to Resolve Error 0x8004210B:

Reduce Email Attachment Size:

If you frequently encounter the error while sending or receiving emails with large attachments, consider compressing the files or using alternative file-sharing methods to reduce the attachment size.

Update Outlook:

Ensure that you have the latest updates and patches installed for Microsoft Outlook. Outdated software can sometimes cause compatibility issues leading to errors.


Facing Outlook Error 0x8004210B can be frustrating, but with some simple troubleshooting steps, you can resolve the issue and restore your email functionality. By following these all steps, you can overcome this error and continue using Outlook seamlessly for your email

Outlook Error 0X8004210B errors are caused by a corrupt or missing Microsoft Outlook-associated file, sometimes due to malware infection

  1. Check SMTP Settings
  2. Disable Antivirus.
  3. Check and Install Pending Updates.
  4. Try Safe Mode.
  5. Repair or Create a New Profile.
  6. Repair the Outlook Data File.

SMTP is stands for Simple Mail transfer protocol. which is is used most commonly by email clients, including Gmail, Outlook, Apple Mail and Yahoo Mail. 

The Outlook error message is: 0x8004210B Your POP3 server is providing inconsistent information.

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