I am relatively new to both C++ and the Client SDK. I am attempting to send data via the plugin command to a specific clientID but it does not seem to be working. It repeatedly gives invalid ID errors.

https://gyazo.com/84322411deb0fc997a801ebfeeb538e3

I've spent a while trying to troubleshoot why this isn't working an I honestly just have no clue, I found one other instance of someone having the same problem on this forums from 2013, but there was never any replies to the thread where they posted about it. This issue is really stalling everything I've been working on so I would greatly appreciate any help anyone can offer! Thank you.