Leaflet map not rendering in IE 11

The following app with a leaflet map and markers, DT table, and ggplots works completely when using firefox, chrome, and my android phone to open. But on IE 11 and windows 7 enterprise the leaflet map does not render. The DT table and plots work. Any suggestions?

https://mnriverecologyunit.shinyapps.io/mn_geomorphology_data5/