Why is Outlook rejecting my Username

Question

I am using my normal email address, and have changed my password, but I am denied access.

Error code 0x800CC91. Then - 'Plaintext authentication disallowed on non-secure (SSL/TLS) connection.'

This means nothing to me... what should I do?

Answer 1

The error code 0x800CC91 indicates that there is an issue with the authentication method being used by Outlook. The message "Plaintext authentication disallowed on non-secure (SSL/TLS) connection" suggests that your Outlook is trying to connect without using a secure connection, which is not allowed for security reasons.

Here are some steps you can take to resolve this issue:

1. Check Your Account Settings: Ensure that your email account settings in Outlook are configured to use SSL/TLS for the incoming and outgoing mail servers. You can find these settings in the account configuration section of Outlook.
2. Update Server Settings: Make sure that you are using the correct server settings for your email provider. For example, the incoming mail server should typically be set to use port 993 for IMAP or port 995 for POP3 with SSL enabled, and the outgoing mail server (SMTP) should use port 587 or 465 with SSL/TLS.
3. Test Connectivity: You can use the Telnet command to test the connection to your email server. This can help you determine if there are any network issues preventing a secure connection.
4. Contact Your Email Provider: If you are unsure about the correct settings or if the issue persists, it may be helpful to contact your email service provider for assistance.

By ensuring that your Outlook is set up to use secure connections, you should be able to resolve the authentication issue and regain access to your email.