frida killed

[irina1290]

When I try to run Frida server I receive : "j6primelte:/data/local/tmp # ./frida-server"
I get the message of : "Killed"
When I tried to google it and search it in the issues I found no suggestions.

I saw in one youtube video someone doing : "./frida-server &"
Tried it aswell and I received output of: "[1] 19988"
but I have no idea if it means that is running.

Anyway after it I tried to run the following command: "frida -U -f SOME_APP_PATH -l SOME_SCRIPT_PATH --no-paus"
and I received the output of : "Failed to spawn: need Gadget to attach on jailed Android; its default location is: C:\Users\User\AppData\Local...."

Googled it and it seems that this messages means that my frida-server is not running so I understood that I got to the first step again.

I'm using it on a Samsung J6 device.
Android version : 8.1.
Frida version: frida-server-15.1.12-android-arm.xz

Help would be much appreciated.
Thanks in advance.