I have an X3 and what I'm seeing is that NiceHash basically reports zero hashes when I point it there for several hours.

Other pools will report hashes but the Rejected Hashes outpace Accepted 10:1 even though there seems to be no problem with the machine. (And when I've pointed to the highest difficulty ports.) Either Bitmain created a horrible machine, or the pools just aren't able to take its hashrate.

I'm no stranger to mining at a loss temporarily -- those losses have generally turned into gains for me after holding long enough. But earning tiny amounts of barely worthwhile coins is not even worth the X3's low power consumption. Sad because this is probably the only modern Antminer that's actually appropriate for home use. If only it broke even. Frankly, it's not even good as a heater!

I will probably point it toward one of the Monero forks for a while before fully giving up on it. In truth, ASIC backed Monero should be every bit as secure as normal Monero and with the power of greater PoW behind it. But whether the market accepts that or not is another question.