Original message from UPS:
The requested billing option/payment option is unavailable with the selected shipment indication type for a shipment to a UPS Access Point.

Explanation:

When shipping to Access Points for dutiable destinations, it's required that the shipper is marked as payor of customs/duties. This can be set on the chosen shipping rate.

How to fix:

In order to fix, click on your shipping rate name to access it within your order channel.

In here, check the add on box for "Bill Receiver"

and scroll down to the new drop down field under Service parameters "Bill Reciever Charge Type" and set it to "Transportation & Duties & Taxes".

Remember to update the shipping rate and try shipping the order again.