I switched to different SFP+ DAC cable with same results. I tested with these cables so far: https://www.amazon.pl/dp/B079QT194T?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1...

@Joseph-TP Hi, I wanted to use SFP+ port in 3rd scenario to connect to Hisource 4x2.5G + 2xSFP+ switch to extend number of LAN ports with 10G link, by using DAC cable. This worked with both Asus...

I noticed that the SFP+ can't be used as a LAN port. It just doesn't work. I want to connect my switch via 10G SFP+ and I can't.