My Apple Macbook Pro is having issues connecting either not at all or very slowly to a number of applications.

Firstly my IOS will not update using this system but will on my work network. Neither will my Apps through the APP store. Microsoft Outlook often takes a while to send/recieve mail and sometimes needs to be closed and opened before it starts working with this. Cisco WebEx meetings also do not log using the desktop app for this, it fails to connect.

Please help, any thoughts greatly appreciated. I have just updated the DNS and this helps a tiny bit but nothing really. 

My other iPhone devices seems to be fine. My Macbook has no firewall/parental controls etc so I'm not sure.