J110m Android 5.1.1 root

Hi All,
I need some help well a lot of help, I have spent 3 days trying to root this phone so I can unlock it.

I have an Octopus Box and z3x however its saying my phone needs to be rooted first.

I have tried all the one click solutions like Kingo Root / IRoot / One Click Root etc but they all fail.

Octopus help menu says I need to manually root then I can unlock using the Octopus box.

How do I manually Root this phone, J110m Android 5.1.1 (I have a feeling its because the version is 5.1.1)

I would really appreciate any help and suggestions on how to do the root on this phone? I have about 50 phones to do:(

Thank you and hoping someone can help me

i try prerooted frimware but hang in samsung logo