While running load test we are getting below error “NL-NETWORK-01”?

In my test script I’m doing Zip Downloading in my application. The process time in the server side can take up to 4 minutes. Running a test with 20VU in 6LG's at Neoload 4.2.2

Here we Observed that 50% user are failed to download i.e 10 VU are failed every time.

Thanks,
Chinnikrishna.