I use a Samsung tab S 8.4 - this is an older version of the same tablet you have.
I have noticed once in a while that the tablet Wi-Fi shows the Spark-RC connection is "not available" or, the first time, it did not even appear.
My solution is to power off the RC, then power the RC back on, wait for the green LED, turn off Wi-Fi in the tablet, then turn Wi-Fi back on. Most of the time the Spark-RC connection will become available, but a few times I have had to repeat this procedure a second time.