What he said... For example the Molex 3M that shipped with a Nutanix block didn't work but then some 1M Amazon knock-offs worked beautifully. Almost seems like many of the 1M work without issue but there is a forum thread >> https://community.ubnt.com/t5/UniFi-Routing-Switching-Beta/US-16-XG-SFP-SFP-DAC-Compatibility-List/td-p/1752736