I just noticed that all of my item maps on historicmt.org are blank grey but still have a pin. I can zoom out and get a map, but when I try to zoom in I get a blank grey page.
The problem is intermittent, it looks like. If you look at your browser console when the problem is happening, you’ll probably see a bunch of “429” errors, basically this is the server hosting the map tiles complaining that you’re using it too much.
It looks like you’re using the Wikimedia tileset, so maybe they’ve changed their polices about people using those tiles. Try configuring the plugin to use a different base map.