Outlook Error 0x800ccc78 Unable Send Message Repair

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“Outlook Error 0x800ccc78 Unable Send Message” is one of the Outlook errors that is becoming a problem for many professionals. When sending an important email or a chat with an online lead, if you see an error: “Send the reported error 0x800CCC78 : “It is not possible to send the message. Please check the email address in your “Account Settings”, how do you feel?

You will be frustrated, of course. Most users tap the “X” (Cross) button in MS Outlook and update it again, provided that things return to normal. But that doesn’t happen. Fixing the Outlook 0x800ccc78 Unable Send Message error is not so easy. You need to acquire technical knowledge to correct such Outlook errors. In this article, we will discover a simple but effective way to fix the Outlook 0x800ccc78 error.

The Outlook 0x800cccc78 error in Microsoft Outlook occurs when something is wrong with email authentication or when SMTP (Outgoing Server) settings are not verified.

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Therefore, compiling and executing a specific server authentication (SMTP) can correct the error code 0x800ccc78 in MS Outlook. But changing the default settings of Outlook programs can be a tricky task for a beginner or for someone who doesn’t have a thorough knowledge of them.

Causes of the Microsoft Outlook 0X800CCC78 error

You can’t expect to solve this problem if you don’t know the real reason.

So let’s find the reasons.

  1. SMTP authentication
  2. mail relay
  3. Sending an e-mail from an invalid e-mail address
  4. webmail

Configuring Outlook settings

Verify Outlook settings

  • Open Outlook
  • From the Tools menu, select Account Settings. The Account Settings field appears.
  • Make sure that the E-mail tab is selected. Your email account will be displayed, usually named mail.yourdomain.com.
  • Click on the account to highlight it, then click on the Edit icon above. The Internet mail settings are displayed.
  • Click on the Other Settings……. button in the lower right corner. The Internet Mail Settings field appears.
  • Click on the Outgoing Server tab page.
  • Check the box My outgoing server (SMTP) requires authentication and make sure the box Use the same settings as my incoming mail server is checked.
  • Click OK to close the Internet E-mail Settings box.

IMPORTANT: Do NOT use the “Test Account Setting…” button to test the settings. It will fail.
Click the Finish button to close the Internet E-mail Settings box. Click the Close button to close the Account Settings field. � SMTP authentication is now enabled.

Disable or uninstall antivirus protection.

For other suggestions, visit your antivirus manufacturer’s website or turn off your antivirus software. And disable the router’s firewall. If you have determined that Outlook is working properly after disabling the antivirus software, we recommend that you uninstall it and reinstall it with your delete tool.

Create a new Outlook profile and reconfigure your email client.

  1. Go to the Control Panel, click on Mail Option.
  2. Click on Show Profiles.
  3. Click on the Add button
  4. Enter a name for your profile.
  5. Outlook 2007 and earlier versions support AutoDiscovery. This will automatically configure your email account. Enter your name, email address and password and Outlook will attempt to configure the profile. If this does not work, go to “Manually configure server settings or other server types” and continue.


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