Jenkins build for Xamarin.Android project with Signing and Alignment
Does your store password have special characters in it? You would need to escape those. Instead of
-storepass $STORE_PASS
try
-storepass "${STORE_PASS}"
If that doesn't help change your store password to something using only alphanumerics (no special chars). Alphanumerics do not need to be escaped on the command line.