Getting error while upgrading an existing AT&T line from Samsung.com

I also ended up buying directly from AT&T shop leaving Samsung offers behind. It looks like some Samsung to At&T API call issue.  Mostly issue seems from At&T webservice consumed by different vendors.

Just wanted to add another data point that I am also unable to log into my AT&T account at checkout through the Samsung website when trying to preorder a Galaxy S23. I am able to get past the 4 questions and get to a pop-up window for 2 factor authentication, but the window times out when I enter the short code and I don't get logged in. Really frustrating and also spent considerable time on the phone with both Samsung and AT&T support today trying to solve the issue to no avail. 

Same here. They must not care. Maybe we shouldn't give them our business?

I had similar problems trying to go through Samsung to upgrade two of my Verizon lines. The difference financially was not enough for me to lose out on the promotion so I finally just went through Verizon directly. Samsung needs to get its act together.  I've read complaints about upgrading through Samsung every year. This is the first year I tried it now I understand how frustrating it is. 

Having same issue at the two factor authentication 

I called AT&T and Samsung customer support again. AT&T didn't see any issues on their end or with my account. Samsung kept denying there could be a problem with their website. Later, the Samsung rep emailed me and said AT&T had locked my account for 45 days due to excessive attempts to log in (which I don't think is true). He recommended I buy the phone unlocked through Samsung, which defeated the purpose of the trade in special. I ended up just buying the phone through AT&T like the other folks in the thread.

"As per your concern . you are facing issue in placing the order . As you are trying yo place the order again and again, AT &T have locked your account . As At &T is locking the amount of customer who are unable to place the order for 45 days. 

I will suggest you to place the order for unlocked phone as you will be able to use AT & T sim in the unlocked device. "

SAME ISSUE S23 PRE-ORDER. (Edited per community guidelines) SAMSUNG!

Those of you that have this issue, are any of you on a Signature AT&T discount plan through an employer or previous employer? I have the same issue and wonder if that Signature discount is what causes the account to be ineligible at samsung.com. I have had this same issue for you BTW, and am currently trying to upgrade and it is still the same ole problem. A number of years ago, you could check out from samsung.com without immediately connecting to AT&T, but i guess they don't do that now, likely because of the trade-in promo.

Interesting! At the time I was having the issue, I was on an unlimited starter plan getting a discount for being a healthcare worker. Maybe the discount is the problem? 

I think i have confirmed the Signature program is the problem. @ATTHelp what is the deal with that??? I use a friends phone number and last 4 SSN to test the connection between samsung.com and AT&T and it worked. My friends account is NOT on a signature program.