You are probably rendering with LightWorks, but assigned your colors in the internal engine mode of the materials dialog. You need to switch the materials dialog to LW mode and click the button 'match with internal engine' to get the color/texture over the the LW side of things. You will find that you have much more control over the material/shader appearance with the LW material settings as well.
That aside, remember that colors change depending on the color of light falling on them ... so be prepared to deal with that too.
Cheers,
Karl
One of the forum moderators
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB