Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 868a7d8d3f7ef524618dc10c301c0e8f9c3dd83a00dcc81bd309b74a5b8e481d:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

error: pre-condition failed: listing has already been purchased
   --> 4eb8a10cb9f87357.NFTStorefront:243:16