iPerf: "error-unable to create a new stream: Operation not permitted."

[m10]

The iperf clients (both iperf2 and iperf3) show this behavior for iOS 8.x versions.
Could someone from the toolAPP team confirm they can reproduce this?
And after that, is there any intend to solve this? Is it very difficult? etc...

Sorry for pushing this,
M10

The iOS device shows the error and no additional information
   - iOS 8.2 on iPhone 6+ AND iOS 8.1.1 on iPhone 4s AND iOS8.3 on iPhone6+ and iOS8.3 on iPhone5
   - HE.NET Network Tools Version 1.3.1.226
The server shows an established connection and continued status
   - Server: Ubuntu 14.04.2 LTS
   - iperf3:  3.13.0-46-generic