How to enable Spotlight search in NAS attached folder with macOS Mojave 10.14.4?

I'm using Synology NAS for my file storage solution. It has been doing great, except one thing. I am unable to do Spotlight search to any of my network drive. I have enabled the indexing in my Synology server, but this does not help either.

How can I enable it correctly? Thanks.

I'm looking from long time ago a NAS solution for Mac OS networks with Spotlight search features but at this moment doesn't works in Asustor or QNap NAS for example (Synology is the same at this moment). I've tryed with this two brands but at this moment you can't find a way to do this. For this reason we must continue with disks connected to Mac OS servers machines.