BT Yahoo! Mail problems: error code 0x800CCC90 - Client response invalid

This error is usually caused due to your account name or password being entered incorrectly. To resolve this error please follow the instructions below:

  1. Launch Outlook Express
  2. Once open please click on Tools
  3. Click on Accounts
  4. Select the Mail Tab
  5. Highlight the relevant account - once highlighted blue, please click on the Properties button
  6. Click on the Servers Tab

    6a. Under the section labelled Incoming Mail Server please check you've entered your username in the text box labelled Account Name:, in lowercase.

    6b. Please check you've entered the correct password in the box labelled Password:. Make sure that the Remember Password box has been ticked.

    6c. Please ensure that the following two boxes are not selected:
    Log on using Secure Password Authentication
    My server requires authentication

  7. Click on the Apply button and then the OK button
  8. Click on Close to return to the main screen of Outlook Express.


Further information

If you're having other problems with your emails or you're receiving other error messages, please use the link below for further information about error messages and how to resolve them:

Using the error message to help fix a fault in BT Yahoo Mail >


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