Rooting HTC desire 610

Hi.I get this error while trying to root my phone:
C:\Users\K****iz\AppData\Local\Android\sdk\platfor m-tools>fastboot flash recover
y twrp-2.8.7.0-a3ul.img
sending 'recovery' (11580 KB)... OKAY [ 2.158s]
writing 'recovery'... INFOsignature checking...
FAILED (remote: signature verify fail)
finished. total time: 4.035s
My phone has s-on and tampered. I checked some forums and it said I need to s-off to root. How can i root or s-off my device?I tried rooting with clear d one click root tool too but it gives the same error. Any help will be appreciated. Thanks