iperf3: error - unable to read from stream socket: Resource temporarily unavailable

This error message indicates that the iperf3 tool is unable to read data from the stream socket because the system resources required for the operation are temporarily unavailable. This could be due to a variety of reasons, such as network congestion, insufficient memory or CPU resources, or a problem with the socket itself.

To resolve this issue, you can try the following steps:

1. Check that there are no network issues or congestion that could be causing the problem. You can use network monitoring tools such as ping or traceroute to identify any network issues.

2. Check that your system has sufficient resources, including memory and CPU, to run iperf3. You can use system monitoring tools such as top or htop to check the system resource usage.

3. Try restarting the iperf3 process or rebooting the system to clear any temporary issues that may be causing the problem.

4. If the problem persists, try using a different port for the socket or adjusting the socket configuration settings to see if this resolves the issue.