Material Design - text colors don't maximize contrast

1. How do I fix color contrast accessibility issues?
2. How is color relevant in material selection?

How do I fix color contrast accessibility issues?

What to do (in short) To fix an Insufficient Color Contrast error, you will need to ensure that flagged elements meet the minimum required ratio of 4.5:1. To do so, you will need to find the hexadecimal codes of your foreground and background color, and test them in a color contrast checker.

How is color relevant in material selection?

Color helps express hierarchy, establish brand presence, give meaning, and indicate element states.