iOS export error

I wanted to test my game on my apple device, and I was surprised to see this message :

Error building Player: SystemException: System.Net.Sockets are supported only on Unity iOS Pro. Referenced from assembly 'Assembly-CSharp'.

I googled it, and if my conclusion is correct, it has something to do with multiplayer/networking .. I'm still a big amateur when it comes to these things. I've only been using Unity Free features and my game doesn't require networking at all.

How can I solve this problem ? Any help would be greatly appreciated. Thank you