Unable to Add Default Esri Basemaps to Custom Group

[DuncanWalser1]

For some reason, the button to add the default raster or vector Esri basemaps does nothing when clicked on. The group is set up as "Public", I've tried doing this in multiple supported browsers (MS Edge, Firefox, Chrome), I have all ad blockers turned off. Clicking on the button does not yield a confirmation or an error, nor does it refresh the page.