If a newly added device is available in the Administration section, but not Security Manager, then it is due to it not having a normalized revision.
This can be caused by either a retrieval or normalization issue.
Troubleshooting device retrievals is covered in this article.
If the device revision does not normalize, then we need to check further using its Support Files, however these are only available from Security Manager.
To access a device in Security Manager you need to manually update the URL in the browser.
First open the device in Administration section, the URL will look similar to this
The id=2 at the end shows the device ID for the device.
Next open Security Manager and access a working device, its URL will look like this
Manually update the number between device and dashboard to the one collected in the previous step.
Then press Enter to load the page.
You should now see the new device and will be able to access its Revisions via the Change menu, Revisions page.