Thank you for contacting FeePay support. We are aware of this issue and are investigating the cause. In the meantime, there are a couple of items to try.
1) Once logged into FeePay, from the Black toolbar, click the drop down by your name and select "Your Account"
Find your student and click on the little pencil icon to Edit. If the Relation is blank, choose Child. Then scroll down and click Save. Some may already be set to Child, if so, click Save.
Then try your transaction again. If your transaction still errors out use the back button on your browser then click Pay again, you may need to repeat this 3-5 times in order for the payment to go through. Be sure you see the error message before clicking the browser back button.
2) Some users have found success switching browsers to either Safari or Firefox to complete their transaction.
Please let us know if these helped and if we can go ahead and close the ticket.
We apologize for this inconvenience! Thank you for your patience as we work to resolve this.