Can't disable Unity's Splash Screen with Unity Plus Account

I just bought unity’s plus license for the solo purpose of removing the unity’s splash screen, but guess what i can’t uncheck the unity logo’s checkmark in the player settings. Moreover, it looks like it has still cached the unity’s personal account and the disable unity’s splash screen checkmark is not intractable (greyish colour). what do i do?
i’ve tried signing in from three different systems, one windows and two mac
i really need to submit my project!
PS: I’m using unity 5.6.0f3
platform Mac

Hello. I had the same problem until updated my Unity Editor.

  1. Inside Unity Editor go to Help → Manage License…
  2. Click “Activate new license” button
  3. Enter the serial received by email from Unity
  4. It will automatically check and OK it, after which you click Next, the skin changes to DarkUI and you can now remove the “Made with Unity” logo, or the entire splash screen.

P.S. I read on some threads that you might also beforehand will need to assign this license to a seat in your organization through Unity ID account page. I had it done already so had no problem with it.

good luck!

Same as @cabertevon
I did activated a license, but beside having a wonderful dark skin, the unity splash logo stay, whatever setting I choose