Curious - this seems to work fine for me and I've tried a few different browsers.
Maybe your browser is blocking the map - you could test it with a different browser perhaps, or check the settings in your browser to ensure it isn't blocking it.
You could also check that the maps are loading OK on other sites, such as https://e-voice.org.uk/demosite/
Thanks
Joe
Ah - OK - it's a firewall issue of some sort. Please ignore. Sorry.