The server responded: 421 Cannot connect to SMTP server

I am using Microsoft Office 2016 with Outlook and setup my email information as per the old computer - all works fine until I try to send an email when i am in USA I can receive emails but when I send then they remain in the OUT box and an error code is as follows

The server responded: 421 Cannot connect to SMTP server ((as the attached))

Help - Need advice ASAP as emails are piling up

Question Info

Last updated October 29, 2019 Views 6,738 Applies to:

Hello Abdul Rahman,

Welcome to Microsoft Community.

To resolve this issue we need more information. Let us know the following.

What is the type of email account you have setup in Outlook 2016? For example POP3, IMAP, Exchange Active Sync (EAS) or Microsoft Exchange. To check the type of email account configured in Outlook 2016 click on File > Info > Account Settings > Account Settings drop-down. EAS account refers to, or email accounts.

This issue happens when the Outgoing Server (SMTP) information is not proper or correct. Since you are travelling and while in the USA the Outgoing Server Address and information should match that of the local ISP there. You need to change the Outgoing Server settings for your email account while in the USA to make sure that the account is able to send emails normally.

  1. In Outlook 2016 click on File > Account Settings > Account Settings drop-down button.
  2. Double-click on your email account.
  3. Change the Outgoing mail server (SMTP) address to match your local ISP information in the USA.
  4. Click on the More Settings button and then click on the Outgoing Server tab.
  5. Check and make sure that the box for the option: My outgoing server (SMTP) requires authentication is checked (ticked).
  6. Also make sure to select the radio button option below: Use same settings as my incoming mail server.
  7. Also, click on the Advanced tab make sure that the Outgoing Server (SMTP) port number is set according to your local ISP’s information in USA.

Save these settings and test if the account works fine and is able to send emails normally.

Hope the above information helps.

Thank you.

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