Unable to create new users in Zoho CRM

Unable to create new users in Zoho CRM

I have tried to create several new users with emails that I know are unique.  The people I am trying to add have not used Zoho before, but I am still getting the message: "Zoho CRM ID already exists. Please use a different Zoho CRM ID."  Why would this be happening?  I am using the free version to start with an only have one user so far, not feeling very confident about this so far.