Trying to make a payment to a vendor.

Description

Hello,
This is a newly created profile but I am trying to determine why we cannot send a payment of $19,000 USD to a vendor. We were able to send out $1,000 – but now any amount above $100 it requests that we « add a payment method ». We are hoping to use the same American Express Business Card that we used to send the initial $1,000 to send the remaining amount. Any ideas?
Thanks in advance,
DotDotDotInc.