Widget NONE/NULL on client, not server.

I have a simple ui element (HPBar[ProgressBar]) that I add to my scene on game start.

(This is in my character actor blueprint)

and the result of that looks good:

And in this game, I have my client and server able to fire projectiles. When the projectiles hit something, they explode and apply damage to any character in the radius. I know this is working. Here is a screenshot where I moved both characters right next to each other and fired a projectile. This projectile detonated and hit both characters for some damage.

You’ll notice that on the server, the health bar has correctly updated. On my client session however, this is not the case. The blueprint block that updates the health and HPBars is not working on my client server, it updates the health but NOT the HPBar. The error I get is the following:

It seems that my HPBar variable is none? I suspect I’m not setting it correctly on the intialization. Can anybody pick out what I’m doing wrong here?