Won't suspend if system is set to lock on suspend

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Hey guys,
I'm fairly new to linux lite but so far I love it! ;D There is just one problem I have, and that is that my laptop won't suspend when I close the lid. In power manager, I have the laptop lid action set to suspend, and I want it to display the lock screen on wake from suspend. To do this I just thought I needed to tick the option "lock screen when system is going to sleep". I tested it out by closing the laptop lid. I waited a long time and I could still hear the laptop fan running and the light on the front of the laptop wasn't blinking. It works as expected if I untick "lock screen when system is going to sleep" in power manager. I'm pretty sure this is a bug but I'm not sure if there is something I'm doing wrong. Is there any way I can fix this?
I am on Linux Lite 3.8 32 bit.
Also, I have searched the internet and changed many settings and haven't found any solutions.

Hi Riley,

I have had some suspend/wake issues, but my approach is to just use the Logout menu and click on suspend, and it works right away. At the end of the day I then close the lid. Opening the lid next morning wakes the system.

I am open to correction of course, but my understanding is that laptops come with a version of Windows which is not generic, i.e. it is customized to suit the particular manufacturers hardware and features. Then when I install a generic Linux OS I don't expect all the hardware actions (e.g. closing lid) to work the same way, so I use the menu. A very small concession for a lovely Linux OS!

I don't have experience of using Lock-screen I'm afraid.

Linux Lite 3.8 64bit, Dell Latitude.