It's always bad to give advice like this, but....
First, If it's under warranty don't do anything that might void it.
These are things that you could do:
Visually check the cable to see if you might have bent the center conductor.
Do you have a meter? I'd ohm out the cable to check for a short.
If Yes (shorted) then try another cable. (RG 59 will work in a pinch.)
The LNB could be shorted instead of the cable. The impedance should be 75 ohms.
The Fortec input could be shorted as well.
If it were mine, (Might not be recommended by Fortec.) I'd disconnect the cable and see if the error message went away.
Since it's new, and if you don't detect a short in the cable or lnb, I'd take it back (obviously).
I don't know what sort of overload protection the Fortec might have, but it obviously has something! Good news.
Good luck!