RWD(beta)-CSS Color Makers - Stuck on step 49

Trying to pass step 49, but validation fails. What am I missing?

.red {
  background: rgb(255, 0, 0);
}

Error:

 Don't give up. Here's a hint to get you thinking:
Your .red CSS rule should have a background property with the value rgb(255, 0, 0).

Step49:

@andras.nemeth.hu if u have some extensions like AdBlocker please switch them off, reload the page, and try again.
Hope that helps!

@stefan2007octavian Thanks for your reply. I had only one extension and that should not mess with it. I turned it off, restarted the step and got same error. I have done over 100 steps already in this ResponsiveWebDesign(beta) curriculum. This happens in latest Firefox.

For curiosity, I tried this step in Chrome and worked fine. :confused:

Yes, that’s a big problem to FCC…
Because of that, it’s recommended to work on it on Chrome…
Without extensions, because they can affect tests…