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    Nintex Knowledge Base

    Error "The SMTP server requires a secure connection ... 5.5.1 Authentication Required"

    Status: Validated

    ISSUE
    When running a DDP, the following error might occur: 

    The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required.
    ERROR CODE
    RESOLUTION

    Option 1

    Disable 2-step authentication or use another email that does not have the 2-step feature on.

    Option 2

    If using a Google domain, create a more complex password (include combination of uppercase letters and symbols)t. If the issue persists, try the following:

    While logged into Gmail, click the account picture in the top-right corner and navigate to My Account > Sign-In & Security. Scroll down and click "2-Step Verification" > App-Specific Passwords > Manage application-specific passwords > Create new App password. Use the new password in the SMTP delivery option settings.
    ADDITIONAL INFORMATION
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