Find My Mac can't find MacBook

So, Apple Chat support confirmed all settings were correct but it wasn't working. They then had me do this, which fixed it. I would never have figured this out on my own!

1. Shut down your Mac.

2 Press and hold the power button again. As you continue to hold it, your Mac turns on and loads startup options. When you see “Loading startup options” or the Options icon, release the power button.

3 Click Options, then click the Continue button that appears beneath it.

4 If asked to select a volume to recover, select your startup disk, such as Macintosh HD. Then click Next.

5 If asked to select a user you know the password for (i.e. Me), select the user, click Next, then enter the password they use to log in to this Mac. 

6 When your Mac has successfully started from Recovery, it shows a window with utilities, such as to restore from Time Machine, reinstall macOS, and use Disk Utility to repair or erase your startup disk.

When you see the macOS utilities window, choose Utilities > Startup Security Utility from the menu bar at the top.

And then on the menu bar, there should be "utilities" that is where you will click the "Startup Security Utility" from the menu bar.

Ensure Full security is selected.

When you're asked to authenticate, click Enter macOS Password, then choose an administrator account and enter its password.

Thanks,

I had already done that and it says it's on. And the restart too......no luck.

This is what I mean in the attachments, in the iCloud menu it's on, but under 'Devices' it is off, with no option to turn it on.

PJ

[Edited by Moderator]

I have logged out and into iCloud a couple of times, restarted the MacBook, and when asked if I should allow Find My Mac to find it, I have said yes. I have then re-checked the settings in iCloud for Find My, and the Location Services is on fro Fund My, and still in 'Devices' on iCloud, Find My is Off and the Mac cannot be found. Bah! So frustrating.

PJ