Whats the problem with my videocall system?

I’m having a problem and I belive you can help me to solve it.
I’m a student and i’m trying to create a videocall in my game with Unreal Engine 4.
It’s not a trivial question, and i’m suferring a lot with that.
First, let me try to explain my idea, and then i got some images of my blueprints.
Its a multiplayer game (of course) but with ONLY 1 server and 1 client. I don’t need more than that.
Then, I create two MediaPlayers, one to recieve my own webcam image, and other (MediaPlayer2) to recieve the other’s webcam. Both are shown in the UI.
In my GameState I created two variables, “URL_Client” and “URL_Server” that basics records the webcam’s URL of each person (that I capture with “enumerate video capture devices”).
So what I tried and failed was: I put my webcam’s URL in MediaPlayer, and it works fine. But when I get from the GameState the the other’s URL and put it on the MediaPlayer 2, it simply does not work. I spent a lot of time with that, and I’m simply lost.
Here you have the screenshots (the language of the engine was Portuguese, but I translated the comments).
I really need your help. Its urgent!
Thank you!