I get this error when upgrading: 'Unfortunately, your account does not currently have any lines available for upgrade'

I am currently trying to pre-order the Samsung Galaxy S10+ from Samsung.com. For the financing plan I click on the ATT Next Plan (as that is what my family has been using for many years, and my brother has recently used for his iPhone 10X). When I sign into my account towards the end of the process, I get the message "Unfortunately, your account does not currently have any lines available for upgrade". However, my line has been paid off since October 2018 and is eligible for an upgrade.

Help would be very much appreciated as I would like to pre-order the phone before March 7th, and I am not sure why I am not able to upgrade my line. Thanks.

***UPDATE*** I believe it may have to do with the bill being over due by a few days as we are not on auto pay. Could this certainly be the case as to why I am having an issue? If so, would paying the bill solve this issue immediately? Thanks.