For a device to work on MyGeotab, it must be provisioned on the MyGeotab platform first. Follow these steps:

1. Login to www,oemserver.com. Contact support to setup an account.
2. Search for the device(s) in question. This explains that process: OEM - Getting Started Guide
3. Select the devices using the tick box.
4. Go to Device Operations->Set Geotab Serial (Provision Device). If you cannot see this option, contact support to be enabled as a "Geotab User".
5. Enter your MyGeotab myadmin site credentials in the pop-up. These are the credentials that should allow devices to be provisioned on your MyGeotab database.
6. Server name can usually be left blank. If you are unsure, leave it blank. If left blank it will use the default value of “service.geotab.com:81”. 
7. Click OK.
8. The system will populate MyGeotab specific information in the "MyGeotab Serial" column,

To send data to Geotab, ensure your device is set to your specific Geotab Connector. See this article to Set The Connector