Dim Light not showing for my PC

For some reason, I don't see dim light correctly. For example I only see bright light for 20 feet, then darkness, instead of bright light for 20 feet and dim light for another 20 feet. I asked my DM but he seems unable to resolve the issue. He said he entered the right numbers, but it doesn't work for me. Maybe I am having an issue with my browser (chrome)? How do I fix it?

Ask him what he entered for the numbers. It should be like this: The first number is the total  distance of the light. Not just the bright  light, but also the dim  light. The second number is where the dim light starts . Not how much dim light there is after the bright light ends.