There may be the following reasons.

1. The normal of this material is reversed, usually happens on 3Ds Max models. You need to go back to the modeling software to check the normal orientation.

2. The color mode of the map is CMYK, currently D5 Render does not support the color mode of CMYK images. You need to convert to RGB mode in other software and re-import.

3. After importing the map to the base color map settings, the color of the base color overlay is too deep to affect the color of the mapping itself.