HUD reference on client

I’m trying to create an action bar for my spell system. However, there’s a “small” but i think it’s an important bug to fix.
There’s a “HUD Reference” to my main widget(it have the main stuff for my character, like health bar, level, action bar…). However, i need to access the action bar from the hud reference to set the stuff in it on the login, but it won’t work because the hud reference is always null when playing on client.
I tried a run on server custom event that sets it but it’ll always be null. I tried making it replicate to server but it does nothing.
How can i fix this “HUD Reference” problem?

Here’s a screenshot of the errors :