Troubleshooting Error Code 0x800ccc78

Sending and receiving email messages can produce many errors. One of the errors produced doesn’t have anything to do with neither the actual transmission nor reception communication process.

Sometimes when your user presses the “send/receive” button they’ll get the following error message: “Sending and Receiving reported error (0x800ccc78). Unable to send the message. Please verify the email address in your account properties. The server responded: 5.0.0. access denied.”

This error can be an indication that your username or even the password is incorrect.

After checking that the email address used is of the correct username domain name format an administrator should check to see if email messages can be replied to recipients, sent to recipients and also received. Most likely they’ll notice that emails can only be received but cannot be sent to or replied to a recipient.

Sometimes the problem is as simple as a typo in the address. Verify that there are no leading or ending spaces or other misspellings in your email address.

Other times the error message will read as follows:  “Sending reported error (0x800ccc78) Unable to send the message. Please verify the email address in your account properties.
The server responded: 530 authentication required.”

In this case the error message is more explicit with its details. An administrator should authenticate to the outgoing server. A review of the sending authentication settings on the “Outgoing Server” tab for the account properties should reveal an incorrect setting. If you are running Outlook 2002 or Outlook 2003 then the administrator should follow these steps:

  1. From the Tools menu select Email Accounts
  2. Next, select the email account in question.
  3. Then click Change
  4. Click on “More Settings”
  5. Then verify that the “My outgoing server (SMTP) requires authentication” box is checked.

Another possibility is that there are two email accounts that are in conflict with one another. If one of your accounts is provided by an Internet Service provider and the other account is your local Outlook email account that you use at work then it is possible that forwarding on the ISP side may have been corrupted somehow. Deleting that account and then recreating it might fix the problem of sending, forwarding and replying to emails.

Also possible is that the error message 0x800ccc78 is an indication that the server rejected the sender’s email address because of an invalid port to send email. If the email administrator suspects this is the problem then they should take corrective measures by following the steps outlined below.

To change the outgoing mail port to 587 in Outlook 2000:

  1. Start Outlook 2000.
  2. Click the Tools menu and then click on Accounts.
  3. Click on the email account that is having problems and then click the Properties button.
  4. Click the Advanced tab.
  5. In the Outgoing Mail (Simple Mail Transfer Protocol – SMTP) box, type 587.
  6. Click the OK button.
  7. Then click on the Close button.

To change the outgoing mail port to 587 in Outlook 2002 or Outlook 2003:

  1. Start Outlook.
  2. Click the Tools menu and then click Email Accounts.
  3. Click on the View or change existing email accounts option and then click the Next button.
  4. Click on the email account that is having problems and then click on the Change button.
  5. Click the More Settings button.
  6. Click the Advanced tab.
  7. In the Outgoing Mail (SMTP) box type 587.
  8. Click the OK button.
  9. Click the Next button.
  10. Click the Finish button.

This can be a frustrating situation when you have an error code that has multiple solutions. But if you are still having problems then there are still a couple more actions to try. One possibility is that the user’s mail profile has been corrupted. Again, an administrator will be the best person to review the email profile for any errors. If it is determined to have been corrupted then the administrator will have recreate it. They can bring up the Control Panel and select the Mail icon. More information can be found about how to recreate a user’s email profile at the following site: .

Lastly, if a virus scanner is running that is integrated with Outlook then an administrator should uninstall the integrated scanner part and then try to send or reply to email. The separately running virus scanner will still provide protection from unwanted viruses.

As you can see there are a number of possible solutions to try when you attempt to resolve the 0x800ccc78 error code problem.

Written by Mike Rede


  1. Yogesh anand · March 8, 2010

    How are you!
    I read your article, which provided helpful for me I was having the same problem
    with the outlook. Thanks for the article it was lovely.

    Yogesh Anand

  2. Graham Judd · October 11, 2012

    Hi I’m very happy I found your article. I was having problems sending email using Outlook Express 6, however after checking the box “My outgoing server (SMTP) requires authentication” it is now working ok again. I had tried tech support with my ISP etc etc but it was your article Re Error 800ccc78 that resulted in success.
    Well done & thanks again.
    Regards Graham

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