Screen Sharing and Network Access when in sleep issues?

Hi,

I am having a new issue that I haven't experienced before, my iMac appears to have stopped allowing me to Wake it from its sleep for Screen Sharing and also drops its Sharing Folder access when trying to get access whilst on my MacBook Pro.

I have followed the steps below but it hasn't resolved the issue:

https://help.edovia.com/hc/en-us/articles/115006932247-My-sleeping-Mac-isn-t-waking-up-for-Screens

I can also confirm that this issue isn't replicated when trying to connect to my MacBook Pro from my iMac with my MacBook waking and screen sharing as well as still giving me access to my shared folders on my MacBook.

Can anyone help, this is now getting very irritating as it used to work and I haven't changed anything? Thanks