How to disable account logoff when closing lid of laptop

I am trying to set up a home cloud server on my old Ubuntu laptop However when i leave it running and close the lid of my laptop of course I get logged out and the process stops.

Is there a way to either completely disable the logoff when closing the lid OR a way to make sure the process keeps running even when I am logged off?

Any help is gratefully received.

/Mark

Is there a way to ... completely disable the logoff when closing the lid ...?

Which operation system do you use exactly?
For me with ubuntu 16.04 LTS I could handle the logoff issue with following standard system settings:

• Turn off the Lock
  system settings > Brightness & Lock > Lock: OFF (Details here)
• Maybe in addition you need to switch on "Automatic Login" for your user:
  system settings > User Accounts > Automatic Login: On