Theme not loading

i keep getting this error everytime i try to load the application

**TypeError: color.charAt is not a function**
decomposeColor
node_modules/@material-ui/core/styles/colorManipulator.js:140
  137 |   return color;
  138 | }
  139 | 
> 140 | if (color.charAt(0) === '#') {
      | ^  141 |   return decomposeColor(hexToRgb(color));
  142 | }
  143 | 