I am getting error: Error: Os { code: 107, kind: NotConnected, message: "Transport endpoint is not connected" }

[bmxmiko]

  Finished release [optimized] target(s) in 2.73s
   Running `target/release/distributed-index`
requests in flight: 0
requests in flight: 0
requests in flight: 0
new client: 127.0.0.1:47920
requests in flight: 1
got all data: 4096 bytes
requests in flight: 1
answered from request 101
Error: Os { code: 107, kind: NotConnected, message: "Transport endpoint is not connected" }

As in the title. Could you help?