By default, Google Chrome does not allow you to log in and authenticate with Google while on Incognito Mode. However, the solution offered by Google is quite simple and only requires a single change on your browser settings.

Access the Google Chrome Browser and enter the following URL:
chrome://settings/cookies

Under the "Sites that can always use cookies" section add the following:
accounts.google.com

And you're done! By doing that, you'll be able to log in to UserGuiding, even on Incognito Mode.