We have discovered that Windows 10 version 1803 and USB dongle licenses need a workaround.
The message from IAR Embedded Workbench can look like this:
Failed to obtain feature 'ARM.EW.DEBUGGER'
The workaround is to configure Windows 8 compatibility mode.
Do the same kind of actions on the eclipse.exe icon.
For the time being, use the workaround. This issue has been acknowledged by our License Management Partner and will be fixed in future releases.