so stupid fix in the meraki Documentation there is a space from com.meraki.sm /.DeviceAdmin this is incorrect . Remove the Space
adb shell dpm set-device-owner com.meraki.sm/.DeviceAdmin
and you will get this
C:\Users\calcuttin\Downloads\platform-tools_r28.0.1-windows\platform-tools>adb shell dpm set-device-owner com.meraki.sm/.DeviceAdmin
Success: Device owner set to package ComponentInfo{com.meraki.sm/com.meraki.sm.DeviceAdmin}
Active admin set to component {com.meraki.sm/com.meraki.sm.DeviceAdmin}
if you have an account already on there you will see this error message
C:\Users\calcuttin\Downloads\platform-tools_r28.0.1-windows\platform-tools>adb shell dpm set-device-owner com.meraki.sm/.DeviceAdmin
java.lang.IllegalStateException: Not allowed to set the device owner because there are already some accounts on the device
at android.os.Parcel.readException(Parcel.java:1692)
at android.os.Parcel.readException(Parcel.java:1637)
at android.app.admin.IDevicePolicyManager$Stub$Proxy.setDeviceOwner(IDevicePolicyManager.java:4731)
at com.android.commands.dpm.Dpm.runSetDeviceOwner(Dpm.java:148)
at com.android.commands.dpm.Dpm.onRun(Dpm.java:96)
at com.android.internal.os.BaseCommand.run(BaseCommand.java:51)
at com.android.commands.dpm.Dpm.main(Dpm.java:41)
at com.android.internal.os.RuntimeInit.nativeFinishInit(Native Method)
at com.android.internal.os.RuntimeInit.main(RuntimeInit.java:262)