The die crack is consistent with a struck coin. The fabric looks authentic. The devices look correct. I see no matches in Forvm's database. To me it looks like a perfectly fine and awesome denarius of Trajan.
Who says that and most importantly why? What condemns this coin as being fake? I also think it's good.
Here's one that looks like an obverse die match, from CNG's archives. Ro's coin looks like it was struck from a more worn die; the CNG coin has more post-strike wear on the high points.
It's Facebook. Anything that doesn't make me laugh there I assume (ya I know) it's not real. I'm just biased against things being "Facebook official."