5 Methods to Fix Outlook Error 0x8004210b

5 Solutions to Fix Outlook Error 0x8004210b

The Microsoft Outlook error 0x8004210b is one of the most common errors you can face as a user when trying to send emails in Outlook. This article will teach you exactly how to fix this error.

Wondershare Recoverit Authors

Oct 13, 2020 • Filed to: Recover & Repair Emails • Proven solutions


Users have been complaining of an inability to send emails on Outlook. The Outlook error message that pops up after trying several times is shown in the image below:

As it turns out, you may be a user with this challenge looking for answers. Well, you have come to the right place for answers. In this article, you will learn all about the error message 0x8004210b, the causes of the error message, and the top five solutions to fix the error. The most important solution is saved for last so carefully go through the solutions to find what you need.

outlook error message 0x8004210b 1

What is this Error Message?

As stated in the description above, Outlook error 0x8004210b is quite common among users of Outlook. However, what exactly does it mean when a user sees this error message? As a user, if you see this error message, it means that the remote server which stores your emails in Outlook is taking too long a time to retrieve or get your emails to be sent. Other symptoms associated with this error are periodic system freeze, system crash, or crash of active program window.

Finding the Causes of Microsoft Error Message 0x8004210b

The following are some of the causes of the error message 0x8004210b:

How to Fix the Reported Error 0x8004210b in Microsoft Outlook

1. Make sure that you are connected to the internet and able to telnet SMTP port number

Your SMTP port 587 or 25 may be blocked by a firewall or your Internet Service Provider (ISP). So, check that you still have an internet connection and telnet on port 25. The steps below will guide you in doing this:

telnet smtp port 1

telnet smtp port 2

To telnet the SMTP port number, do the following:

telnet smtp port 3

telnet smtp port 4

2. Check the Outlook email account settings

Check to ensure that your email account settings are correct by following the steps below:

outlook account settings 1

outlook account settings 2

outlook account settings 3

outlook account settings 4

outlook account settings 5

3. Disable or uninstall anti-virus

Third-party anti-virus programs can cause this error through their interference of your attempts to send emails. You can resolve this issue by uninstalling or disabling the programs through the following:

uninstall anti virus 1

uninstall anti virus 2

uninstall anti virus 3

4. Install available Windows update

Your Windows may be outdated, thereby causing this error message. With the steps below, you can set your system in such a way that whenever a Windows update is required, it will automatically go through:

install windows update 1

install windows update 2

5. Try Outlook repair tool

Some errors run deep and cause more damage than normal troubleshooting can handle. It might seem like all hope is lost after you have tried the above solutions to no avail. You can always try an Outlook repair tool to resolve this issue. Stellar Outlook Repair is the professional tool that is capable of handling all your Outlook repair needs. With this tool, you can fix any error in your PST file on any Windows version you are using. It supports files repairs in different types of folders such as attachments, journals, calendars, schedules, etc.

To use the Stellar Outlook Repair tool after downloading, do the following:

Step 1. Add Corrupt File

Open the home interface of Outlook and add the corrupt PST file using the buttons "Find" or "Browse"

add corrupt pst 1

Step 2. Repair Corrupt File

Start the scanning process by choosing "Repair". Watch for the progress window

repair corrupt pst 2

Step 3. Preview and Save File

Preview the files that have been repaired above once complete

preview repaired pst 3

Now go to the "Home" menu on the display bar and click "Save Repaired File" from the drop-down list

save repaired file 4

The Bottom Line

This error 0x8004210b occurs in different versions of Windows like 8.1, 7, 10, hence it affects a wide range of users. However, with the key solutions in this article, you can fix the error and go-ahead to send that all-important email without any delays. Most importantly, you can trust Stellar Outlook Repair to fix all issues related to your Outlook PST files.

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