Check if any devices is waking up your PC then disable the option that allows them to wake up your PC.
Open Command Prompt and type 'powercfg -devicequery wake_armed' and hit Enter
You will see a list of devices that could wake up your PC.
Go to Device manage locate the device on the list, right-click and select Properties.
Click the Power Management tab and uncheck the box 'Allow this device to wake my computer'.
Click OK .
Repeat these steps for other devices that could wake up your PC.
Open Control panel and click on 'Power Options'
Click on 'Change plan settings' (on the active selected power plan)
Click the 'Change power settings' link.
Expand 'Sleep', then expand 'Allow hybrid sleep'
Turn it off
Click Ok
You need to try 'powercfg - lastwake' and also 'powercfg -devicewake wake_armed' in Command prompt to find out what is waking up your system.
Also check the task manager for running apps, it could be a program waking up the PC
There is a list of hardware that are able to wake your system.
You could go to Power management in Device manager and uncheck 'Allow this device to wake your computer.
Also updating these devices drivers might help.
Reviewed some forums on the subject and they had the same advise. Evidently this is a long standing problyem with Windows 10.
...and Windows 8, 7, Vista.
My nephew just told me, he was having the same issue with Logitech keyboard and mouse combo after a Windows update. He tried several Logitech software versions until one worked.