Invalid Credentials Error

The Invalid Credentials Error means that for one reason or another our tool was unable to access your email account. There are a few things going on and here’s a comprehensive list of the possible problems.

Before trying any of the following steps, try logging into the Google account that is returning the Invalid Credentials Error. This could be the source or destination email account. We recommend logging out of all your accounts and logging back into the correct one, or even using an incognito window.

Complications with Two-Step Verification

  • Two-Step Verification will prohibit the Carbo migration tool from accessing the account. The simplest solution is to disable Two-Step Verification for your G Suite account until the migration has completed.
  • It may be the Captcha page that is hanging up the migration tool. Try unlocking the Captcha and start a new migration within 10 minutes of clearing it. For more information on unlocking Captcha, please read this documentation.
  • Alternatively, create an app password specifically for the Carbo migration tool to access the account. The app password will be used once and can be revoked after the migration has completed. For further reading on app passwords, refer to this Google article.

Less Secure App Access

Google has recently added a feature whereby it blocks sign-in attempts from some apps or devices. Unfortunately, this has resulted in a number of authorization errors not only in third party apps, like the Carbo migration tool, but also in some of Google's non-core G Suite services. If two-step verification has been turned off for the account and the migration tool is still showing "Invalid Credentials," this may be the cause.

  • Follow this link here to find the Less secure apps page, and click on "Turn on" to grant access. We recommend using an incognito window to be sure Google processes the settings for the correct account. 

Verify IMAP Server Information

  • Double check that your source IMAP host server is entered correctly. Note that all host names must begin with either imap:// or imaps:// as a prefix to the url name.
  • Log in to the account that is returning the Invalid Credentials and make sure that IMAP connections are enabled for the mailbox.

A New Account

  • The Invalid Credentials Error can occur when migrating a user account that has recently been created. The user may need login and activate their account before migrations can be run to or from it.

Finally, if the error still persists, please delete the Carbo migration tool from the Google Apps domain, and then reinstall it. Clear the browser cache and retry the migration. If that does not work, please contact us immediately via

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