Dimensions: SendDate (DATE), CountryName
Since we have more than hundred countries and more than a year of data grouped by date in one MDA subject, it seems that heatmap shows only one day for couple of countries and ignores the rest.
Same thing happens even if we filter out to show only last 7 days or we summarize SendDate by weeks.
Heat map usually works fine when it comes to much smaller volume of data - for example creating a heat map from CTA or Account object
In attached example below we're seeing only one week of data and there should be at least few weeks visible and dozen more countries available:
Couple of ideas for additional heat map improvements
