If you're using Now Assistant through a chat bot, the bot authenticates the current user (i.e. you) with Now Assistant to retrieve their info.
If the bot fails to authenticate the user it will respond with the following message: Please login once to your Now Assistant before using the bot.
Message may vary slightly if your organization has customized it
This can happen if one of two things occurred:
Contact your Administrator so they can double check if the above fixes have resolved the issue. If the error persists, please contact the adenin Helpdesk.