I need to root my S5 but every time I try it says failed or device not supported. how to root an s5?

[AC Question]

My phone is running 5.0 lollipop
The model # is SM-G870a

 

[Rukbat]

1. It's an AT&T phone - not many rooting methods support AT&T Samsungs.

2. See XDA Forums for a rooted ROM for that phone.