hEX S & SFP S-RJ01

[msatter]

SFP port can be purposed however you need it to be.
Can you put the SFP into your :AN and connect a PC to it and access the router?
It sounds like hardware issue or negotiation problem between modem and SFP.

Indeed switch of auto negotiation and set speed to 1Gbit.
Those SFP can generate much heat and in the middle of the thread you see my solution for the hEX-s
http://forum.mikrotik.com/t/sfp-module-is-extremely-hot/117746/19