I gıot this achiment 2012 05/17/2012 why ı cant use that legandary bow as a transmog ı opened 3 ticket u didn’t help me u send me auto msg did u tyr wowhead or icy vein or forums ı need help pls fix my problem
Because you cant transmogg legendary items as a base. There are a few exeptions, but the bow is not one of them as far as i now.
Legendaries have never been transmoggable, as a general rule.
are u playing world of warcraft
You can mog it
https://imgur.com/Xmstoo5
However, I recently acquired it so you might have to re-farm it to get it added to your mog tab.
I went on every hunter I had for about 3 weeks before it dropped, I think something like 15-20 tries.
Good luck!! 
game master fix my problem
There are no game masters here - the only way to contact them is by ticket. There’s a long queue at the moment so maybe Afenton’s suggestion will be quicker if it’s not on your mog tab.