Users are authenticated in Kayako by the email address and password. Billing allows several users to have the same email specified in their contact information; in this case it is assumed that all of them represent a single person in reality, which is why they are allowed to log in to Kayako as a single Kayako user.
Billing allows several users with the same email to log in to Kayako only in case email confirmation feature is enabled; it is required to prevent fraud. To enable this feature open System > Settings > Security > Email Settings and set Email Confirmation Required checked).
If several users with the same email try to access Kayako, Billing handles it as follows:
- Only those users will be allowed to access Kayako, who have their emails confirmed in Billing.
- In case none of them have their emails confirmed in Billing – only a single user (with the lowest identifier in Billing) is allowed to log in to Kayako.