If you receive this rejection, this means that your client has a rule on their end that requires the firm to specify the timekeeper on the Fee line items. When the firm created the line items, the line item did not include the timekeeper information.

Solution: This rejection is caused when you choose the Item Type: Total Fees. When you create your line items, use the Item Type: Fee or Exp. Check the rejected invoice and find out for which line item the timekeeper information was not entered. Go to Copy and Edit an Invoice to review the steps on how to copy and edit the rejected invoice to do the necessary changes.