OSX has a feature in that it will allow remote network routers to change the machine name.

Houdini licenses are dependent on the machine hardware and machine name. If the machine name changes, this will invalidate the licenses.

Apprentice, Indie and Commercial Workstation licenses will look to the local machine.

Apprentice users:

Launch the License Administrator and select File->Change Server and press the Local Server button. Ensure it matches your current machine name.

Indie or Commercial Workstation users:

Launch the License Administrator and select File->Change Server and press the Local Server button.
Ensure that the server name matches the machine name associated with your licenses.

If the machine name is different, you will need to rename your machine back to the original to what the licenses were registered with.

If you want to change your machine name, you will need to release the licenses first: FAQ