Resolve 0x8004210a Error in Outlook

[jonshen alina]

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Read More - Resolve 0x8004210a Error in Outlook 

[Akshay_M]

When you are aware of the reasons behind the 0x8004210a error, you can rectify these issues by applying some methods that are mentioned here:

Check the Internet connectivity

Your first reaction should be checking whether the Outlook application connects to the Internet or not. Because Outlook is able to work in the Offline mode, so the users keep working on it without checking the Internet. If the Outlook is working without Internet, then there will be no transfer of emails.
Remove suspicion emails from your Outlook mailbox

The infected emails in your mailbox can hamper the performance of the whole Outlook application. They can stop the application from sending out or receiving emails. If you are aware of such emails, then delete them as soon as possible.
Disable your anti-virus program

If there is integration between your anti-virus program and the Outlook, then the anti-virus can affect the performance of the Outlook. To stop the interference of anti-virus software, then disable it from scanning the Outlook emails.
Delete the older account and create a new one
If the account is damaged beyond repair, then you do not have other option but to delete the older account and create a new one. You can also create a new account through the Control Panel Settings.

Close Outlook and open the Control Panel.
Click Mail (Microsoft Outlook 2016.)
Click Email Accounts.
Click New and create a new account’s credentials.
After creating the account again, try to send some test emails to other account to test the connection.

Apart from these common troubleshooting steps, if things are still as it is, then configure the accurate port numbers and server time-out settings. Proceeding further, the server timeout error 0x8004210a pops up when the Send/Receive operation couldn't be completed in the configured timeout limit. Adding into it, you should also check the port number settings for POP (Post Office Protocol) as the values of POP port no. differ when you configure SSL encryption settings.