When creating a new user account, you may encounter the error message, "Error: This email is already registered to a Cisco Umbrella Account".
The email address is already registered to an account with us, but the account is not a part of your organization.
You must invite the existing user to your dashboard instead of creating a new user. You can do this under Admin > Accounts, then click Invite instead of Add.
After filling out the user's information and clicking Invite, an email will be sent to the email address you specified with a link to accept the invitation. If the user accepts the invitation, they will now be a part of your organization.
The user's status will be Pending until they accept the invitation.