I'll answer my own question with a quick google search ...   "For various reasons having to do with the ordering of messages on iperf3's control channel, the server cannot print summary statistics from the client side. This is a known issue (there are various issues in the iperf3 issue tracker around this problem such as #560 and #314). It's not particularly easy to fix because a solution to this problem would involve changing the ordering or semantics of iperf3's control messages which, unfortunately, aren't particularly well documented. We (ESnet) would be happy to entertain possible fixes." ... View more

Hi Rob Good to know that you go this sorted out, even if you don't know why/what the problem might have been.   I don't see the red cross between the devices as you did.   Craig. ... View more