Adding themes to Sharepoint 365

Hi there

I created a new theme using MS Fluent UI; then exported the code. I then connected to our sharepoint admin portal (using Powershell); 

$ThemePalette =@{{
"themePrimary" = "#ffe000";
"themeLighterAlt" = "#0a0900";
"themeLighter" = "#292400";
"themeLight" = "#4d4400";
"themeTertiary" = "#998700";
"themeSecondary" = "#e0c600";
"themeDarkAlt" = "#ffe419";
"themeDark" = "#ffe83d";
"themeDarker" = "#ffee70";
"neutralLighterAlt" = "#848e99";
"neutralLighter" = "#89939d";
"neutralLight" = "#909aa3";
"neutralQuaternaryAlt" = "#949ea8";
"neutralQuaternary" = "#98a2ab";
"neutralTertiaryAlt" = "#a8b1b9";
"neutralTertiary" = "#c8c8c8";
"neutralSecondary" = "#d0d0d0;
"neutralPrimaryAlt" = "#dadada";
"neutralPrimary" = "#ffffff";
"neutralDark" = "#f4f4f4";
"black" = "#f8f8f8";
"white" = "#808a94";
}

followed by

Add-SPOTheme -Identity NewTheme -Palette $ThemePalette -Inverted $false

but then i then goto "Change Look" in the sites i dont see my new theme.

Any ideas?

Thanks