This is exactly what happened to me!. I followed the onscreen and "expert" instructions and had multiple error and review sessions on the one line associated with either "enter the amount from your 1099K" or "the amount of the proceeds". The only difference for me was my 3rd party was StubHub. There was the total amount on line 1 of the 1099K and there was a box for every month with an amount. Some months contained both baseball ticket sales and football ticket sales and subsequently a mix of losses and gains. I ended up entering every sale (19 of them) with I think 8 ultimately having a true gain. And while I was able to match the monthly 1099K totals to my actual sales, the amounts that would "calculate" in TT were always off and I'd get the same review error. I finally just plugged in a number that it was looking for (that didn't match any total I came up with - e.g., sales, gains, original investment amount, etc.) and it finally moved forward. I know I'm not a dolt and can navigate a basic Excel tracking tool, but either the IRS or Turbo Tax need to figure this process out better. Best wishes for those continuing to navigate this challenge.
