Sometimes after assigning a Payment Center license to a user, the user still cannot access invoices, payments, etc. This could be because the user’s profile does not have the proper access to Payment Center components. To ensure proper access, you can assign permission set Payment Center All Access to the user by following the steps below:

  1. Go to Setup | Manage Users | Users.
  2. Click on the user. Under Permission Set Assignments, click Edit Assignments: 

  3. Add Payment Center All Access to the Enabled Permission Sets section, as shown below: