Bitmain answers quite fast to the open tickets... Although not very helpfull:
Dear Mpenagar,
Your firmware is a little bit older. We have not published the Dec 19 firmware for the L3, so it might not be available. I will check and let you know.
In the meantime, we have heard from customers that there may be issues with Nicehash mining from Antpool, due to the difficulty level. Please do check with Nicehash to see if that is the issue for you.
Regards,
Barbara
Bitmain