Hello Julio,

Welcome to the Community - thank you for your question!

They should not need to login when viewing the invoice. Would you be able to resend the invoice by going to your Invoice list, selecting the drop down action column and selecting Reminder. You can change the message so it does not mention being a reminder, and this will then send out the invoice again.

Let us know if they experience the same issue with the new invoice.

Thanks,

Talia