Outlook error code 21999 appears and displays a message “The connection to the server failed” on the screen. If your Outlook also encounters this error, then you must be wondering why this happened and how to fix it. In this blog, we will answer all your questions and help you fix the error 21999 in Outlook 2016 and other versions.
Outlook error code 21999 occurs when you’re trying to send/receive an email or start an Outlook app. Microsoft Outlook is one of the best apps with excellent mailing features designed by Microsoft with several features such as webmail, task manager, contact manager, calendar, and note-taking. Outlook’s amazing features will not only let you compose or send your email but also help you to manage your email account more efficiently.
This article contains information that shows you how to lower the security settings on your computer or disable security features. You can make these changes to solve specific problems. Before making these changes, we recommend that you evaluate the risks associated with implementing this solution in your specific environment. If you implement this solution, please take the necessary additional steps to help protect your computer.
Every problem has a specific reason behind it, so there are some factors due to which you find difficulties while sending or receiving. To learn what causes this error and how to resolve it, obtain reliable Email Support from tech-savvy or else glimpse on the blog post.
This article provides general methods to troubleshoot problems with sending and receiving emails in Outlook or Outlook Express.
Reasons for Outlook error code 21999
- Poor internet connection takes you to experience the Outlook Send Receive Error.
- Antivirus or firewall software installed on a PC can be the one reason
- Due to incorrect Outlook email account settings
- Due to large attachments
- If there is an Outlook data file error
How to Fix Outlook error code 21999
To work around this problem, use one or more of the following methods. At the end of each process, send a test email to verify that messages can be sent and received without error messages. If you still get the error message, try the next solution.
Solution 1: Make Sure You Are Connected to the Internet
First of all, if you are seeing Outlook error code 21999, it is recommended to check your internet speed. You can’t send or receive emails because your connection is down or you don’t have an internet connection. To check if the system is online, follow these steps:
- First, open a web browser in a computer window.
- Type one of the following addresses in the address bar and press Enter on your keyboard.
- If you can access the site, it means that the internet is connected to the system.
If you’re still having problems connecting to the Internet, see Troubleshoot network connection problems in Internet Explorer.
Solution 2: Repair your Outlook or Outlook Express
Repairing your Outlook or Outlook Express may also resolve the problem.
Follow the step to Repair Outlook or Outlook Express from the Control Panel:
- Right-click the Start button. (Lower-left corner on your desktop)
- Select Run on the pop-up menu.
- In the search box, type Control Panel and select ok.
- Click the Programs and Features on the Control Panel Window.
- To Repair a program, select Microsoft Office product from the list and click Change.
- In the User Account Control Window, Select Yes.
- First, choose Quick Repair and then click Repair.
Note: If Quick Repair doesn’t work on your computer, then you should try Online Repair. Follow steps 1-6 then choose Online Repair and then click Repair.
Here, you should watch the video tutorial on how to repair the Microsoft Office?
Solution 3: Correct the Outlook Email Account Settings
If your internet speed is fast and you are still seeing Outlook error code 21999, change your Outlook email configuration settings. How to properly check the settings:
- Open Outlook first and log in with your valid email address and password.
- Now, go to the “File” menu.
- After that, go to the “Info” column and click on “Account Settings”.
- Under the “Account Settings” window click on the “Change” tab.
- Now click on the “More Settings” tab and select “Outgoing Server”.
- Click the checkbox which is in front of My outgoing server (SMTP) requires authentication.
- Also, select the checkbox of Log on to the incoming server before sending mail.
- Now, click on the “OK” tab and the “Finish” button.
Solution 4: Uninstall Antivirus Software
Outlook error code 21999 usually occurs when antivirus software is installed on the system. Windows Firewall and third-party antivirus software can block access to Outlook. Because of this, you may receive send errors in Outlook. So, turn off your firewall and antivirus for a while and then use Outlook to send and receive emails.
Follow the steps below to log out.
- Open Control Panel and click on the “Network Connections” tab.
- Right-click on the network connection on which you are connected and then tap the “Properties” option.
- Under the “Security” tab turn off Firewall.
Once the problem is fixed and your inbox is up to date, turn on Windows Firewall to protect your system.
Solution 5: Check the Suspicious Emails to fix Outlook error code 21999
Outlook error code 21999 can also be caused by suspicious emails arriving in your inbox. So, look for suspicious spam emails and, if found, delete them immediately. After deleting suspicious emails, you can send and receive messages without errors. If it doesn’t work, choose it.
Solution 6: Repair PST File to Run the Inbox
In Outlook, special folders/files containing email contacts, messages, notes, notes and other personal information are called PST files. When the PST file gets corrupted, you cannot send emails and you cannot receive new emails in Outlook. Follow these steps to repair the PST file.
- Log out from your outlook account first and then start repairing the file
- Open your system and go to “Setting”.
- Click on the “Update and Security” tab.
- Select “Troubleshoot” – let the troubleshot run on its own and the tool will be repaired.
- Open your pst file and look for the following options.
- Restore the pst file
- Move the pst file
- Backup of the pst file
Select these options as per your preference to move data from your current Outlook account to your backup email address and update the system. Then go to your Outlook account and you will receive a new email and you can also send an open email. If Outlook still won’t send an email, read on.
Solution 7: Clean Outlook Mails to fix Outlook error code 21999
Outlook emails need to be deleted or deleted once every few months. Storing too many emails in your inbox can cause problems sending and receiving emails. To do this, proceed as follows:
- Go to your outlook account and click on the “Send Receive” tab.
- Select the option to work Offline.
- Select all the emails from Outbox and move all of them to the Draft folder.
Now the outgoing mail file is clean. This feature is used to send paused emails and receive new ones.
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