If you export or link to a mymaps map/kml then icons might be missing and not showing on the map with the plugin.
I starred this issue, if you can do the same, it might get attention soon from Google.
- Use a white icon
- Select an icon from the option more icons
- use a custom icon (this will use an icon outside of mymaps)
- use kml renderer geoxml and version 3.4 of the plugin (email me for this version)