I've been trying to add our own icons to a custom vector base map style that I've been working on but repeatedly receive a generic error message. The call to action button in the upload menu also seems strange, "Replace icon/pattern" I was expecting something like "Add item" I've tried multiple browsers (Chrome, Firefox) and no dice.
Not sure how to proceed and would appreciate a bit of help here. The icon I'm trying to update is a 64x64 png with a transparency background.