Question:
When using the MapThat Print Map tool, the Print Map is either blank or the popup does not appear.
Answer:
If the Print Map tool does not open a new window, or if that window is blank, this is because of the settings for your Browser on the client machine. In order for the Print Map Tool to work successfully please apply the following settings for these following Brower’s.
Internet Explorer:
Choose Settings > Print > Page Setup > Tick Print Background Colour and Images and press OK. 
Chrome:
Press Ctrl P > In the ‘More Settings’ option > ensure that Select Background graphics is ticked. 
Mozilla Firefox:
In the Option Menu > Select Print > Page Setup and tick the Print Background (colours & images). 