Fixing the Error 'Uncaught Exception: Expected response code 250 but got code "535", with message "535 5.7.8 Username and Password not accepted' When Using a Gmail Account

Overview

When trying to respond to a ticket in Kayako Classic, users might see the following error:

Uncaught Exception
Expected response code 250 but got code "535", with message "535 5.7.8 
Username and Password not accepted.

This article provides information on how to fix the issue.

Prerequisite

• Admin access with "update email queues" permission.

Solution

The aforesaid error was specifically generated while using a Gmail account for sending emails in Kayako Classic.

If you are using 2-Step-Verification with your Google account, you may need to use the App Password to avoid this issue from occurring. The App Password is a 16-character passcode that gives an app (e.g., Kayako Classic) or device permission to access your Google Account and can only be used with accounts that have 2-Step Verification turned on.

To learn about signing in with App passwords, visit the Sign in with App Passwords Google Support article.

Once you have generated the App password, update your login credentials by following these steps:

1. Log in to the Admin Control Panel.
2. From the Home tab, click Email Parser and click Email queues.
3. Select the email queue you want to edit, and from the POP3/IMAP tab, enter the App passcode in the Password box.
   
4. Click Update to save your changes.