Hello... wairuri

on android 4.4.x to 5.1.x the name of the card is usually "/storage/extSdCard"
to be sure, check it with the total commander...
check also the folder on "addons/content/map"
also you can try with a different name instead "addons"

like mine:

has_secondary_root=1
android_secondary_root_path="/storage/extSdCard/SharedMaps"

or post your sys here.....