I tried to run this code and every time I run it shows this result - api

Question

private fun moveMarkerAnimation(key: String, newData: AnimationModel, marker: Marker?, from: String, to: String) {
if (!newData.isRun)
{
compositeDisposable.add(
iGoogleAPI.getDirections(
"driving",
"less_driving",
from, to,
getString(R.string.google_api_key1)
)!!.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe { returnResult ->
Log.d("API_RETURN",returnResult,)
try {
val jsonObject = JSONObject(returnResult)
val jsonArray = jsonObject.getJSONArray("routes")
for ( i in 0 until jsonArray.length())
{
val route = jsonArray.getJSONObject(i)
val poly = route.getJSONObject("overview_polyLine")
val polyLine = poly.getString("points")
polylineList = Common.decodePoly(polyLine) as java.util.ArrayList<LatLng?>
}
handler = Handler()
index = -1
next = 1
val runnable = object :Runnable{
override fun run() {
if (polylineList!!.size > 1)
{
if (index< polylineList!!.size)
{
index ++
next = index+1
start = polylineList!![index] !!
end = polylineList!![next]!!
}
val valueAnimator = ValueAnimator.ofInt(0,1)
valueAnimator.duration = 3000
valueAnimator.interpolator = LinearInterpolator()
valueAnimator.addUpdateListener { value ->
v = value.animatedFraction
lat = v*end !!.latitude + (1-v) * start!!.latitude
lng = v*end !!.longitude+ (1-v) * start!!.longitude
val newPos = LatLng(lat,lng)
marker!!.position = newPos
marker!!.setAnchor(0.5f,0.5f)
marker!!.rotation = Common.getBearing(start!!,newPos)
}
valueAnimator.start()
if (index < polylineList!!.size-2)
{
handler!!.postDelayed(this,1500)
}else if (index < polylineList!!.size-1)
{
newData.isRun = false
Common.driversSubscrib.put(key,newData)
}
}
}
}
handler!!.postDelayed(runnable,1500)
}
catch (e:java.lang.Exception){
Snackbar.make(requireView(),e.message!!,Snackbar.LENGTH_LONG).show()
}
When the site changes from from firebase this result appears
022-04-26 13:19:30.912 23482-23482/com.example.bustrackerriderapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.bustrackerriderapp, PID: 23482
io.reactivex.exceptions.OnErrorNotImplementedException: The exception was not handled due to missing onError handler in the subscribe() method call. Further reading
what should I do to fix this problem