TL;DR We had 11 free-trial users on a paid Colombian legaltech plan over 30 days. Trial→paid conversion: 0% . Spoiler: it wasn't a PMF problem. It was a billing-architecture bug. If your trial doesn't tokenize a card upfront, your cron job has nothing to charge when the trial ends. The user silently downgrades to free, and your "trial conversion rate" is mathematically impossible. Here's how we found it, and the .NET 10 + EF Core fix. Context I'm building NeoJurídico , a court-process monitoring platform for Colombian lawyers. The Litigante plan ships with a 14-day free trial activated via UTM-tagged Google Ads campaigns. Tech stack: .NET 10, EF Core 10, PostgreSQL, MercadoPago for billing, Angular 21 on the frontend. The 0% trial→paid mystery We were spending real money on Ads and getting 11 trials/month. Zero ever converted.…