Now i`m adding array as string to body:
RequestBody body = new FormEncodingBuilder()
.add(\"profiles\", \"[122, 125, 336]\")
.build();
You are currently posting profiles
as a string. You will want to mimic a POST for a checkbox form field for profiles
RequestBody body = new FormEncodingBuilder()
.add("profiles[0]", "122")
.add("profiles[1]", "125")
.add("profiles[2]", "336")
.build();
more info and good reading,