Account Owners login to Customer Center portal within two different pages. The address depends on the payment method.
https://customercenter.targetprocess.com/account/#/login is for users paying by card.
Login is performed with email + password credentials. Access can be granted to other users. User interface has modern theme.
https://customercenter.targetprocess.com/ is for users paying by bank transfer.
Login is performed with License key. User interface has old theme.