Gavelsnipe failed me.

[swarmee]

It has been said that eBay sends Captchas to accounts with weaker passwords since they're most likely to be taken over by bots (computer software) to commandeer auction bids. So you may want to upgrade your eBay account password to something with 16 characters including capital letters, numbers, and special characters. Then update it in your sniping program.

There is a new fraudulent bidding system being employed now to counteract true bidding on eBay, that guys on Blowout have been mentioning has been happening in cards more lately.

Say there's an item worth $400 and the bid is currently at $100. A guy that wants it under value will have one account bid $1000, which will set the new viewable max bid at $105. A secondary account will bid $1010 and then the max bid will show as $1010. Then seconds before the auction ends, the last bid will be rescinded and the first account will win at $105. This is probably subverting the bids of sniping tools because they're watching to see if your listed $400 bid will currently win, which it will not because the bid's at $1010.

https://www.blowoutforums.com/showthread.php?t=1389651