by Anton

January 27, 2021

Microsoft Outlook is an email application available on the Windows platform. It allows anyone to manage their email and also includes other features such as a calendar, task manager, contact manager, notes, diary and web browsing. Although it is a reliable application, sometimes problems can occur, which we will cover today. In this last article, we will look at the error related to Outlook 421’s inability to connect to the SMTP server.

Restart the computer before performing any of the recommended troubleshooting actions below. This action refreshes the operating system and removes the corrupted temporary data that could be causing the problem.

Delete and then add an e-mail account

If this problem occurs immediately after adding the email account, it may be due to poor configuration. Try deleting the account and then integrating again. Make sure you have the necessary information to add an email account.

  • Open Outlook and go to File > Account Settings, select the correct account and click Delete .
  • Press New , select the email account and enter your details again.
  • Press and then and wait until the settings are configured and the test email is sent.

Check that Outlook 421 cannot connect to the SMTP server, but the error still occurs.

Change SMTP port number

SMTP or Simple Mail Transfer Protocol normally uses port 25. If this port is blocked, this problem may occur. You can try changing it to port 465 and then see if the problem persists. Note that this only applies if your outgoing connection to the server (SMTP) is configured over SSL.

  • Open Outlook and go to File > Account Settings, select the email account with the problem, and click Edit .
  • Go to register Advanced and select register Advanced . Then type 465 in the field next to the outgoing mail server (SMTP) and make sure the encrypted connection type is set to SSL.

Check that Outlook 421 cannot connect to the SMTP server, but the error still occurs.

Try disabling the firewall

The firewall monitors internet traffic on your computer. This can sometimes block certain features of Outlook, such as. For example, sending or receiving emails. Try disabling the firewall to see if this is causing the problem.

  • Select Start> Settings > Updates and Security > Windows Security , then Firewall and Network Security .  Open Windows SecuritySettings
  • Select a network profile.
  • In Windows Defender Firewallswitch to OFF. Disabling the Windows Defender firewall can make your device (and your network, if you have one) more vulnerable to unauthorized access.

Check that Outlook 421 cannot connect to the SMTP server, but the error still occurs.

If the problem does not occur, then you need to allow Outlook to pass through the firewall.

Firewall enable

  • Select Start > Settings > Updates and Security> Windows Security , then Firewall and Network Security. Open Windows Security Settings
  • Select a network profile.
  • In the Windows Defender Firewall, set the setting to On.

Allow Outlook through Firewall

  • Select Start> Settings > Update and Security> Windows Security , then Firewall and Network Security.  Open Windows Security Settings
  • Select Allow application through firewall.
  • Select the request you wish to ignore.
  • Select OK.

 

Related Tags:

sending’ reported error (0x800ccc67) ‘ the server responded 421 cannot connect to smtp serversmtp error (421) connection to server failedoutlook cannot connect to your outgoing (smtp) e-mail servercould not connect to smtp host response: 421how to fix outlook smtp erroroutlook error code 421smtp error (421) connection to server failed cpanelsmtp response 421

About the author 

Anton

Leave a Repl​​​​​y

Your email address will not be published. Required fields are marked

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

Be Careful When Torrenting, Use a VPN