Sounds like a connection timeout for me.
This mostly happens when you have Insurgency Sandstorm installed on a HDD ( mechanical hard disk drive )
The loading times will be much faster and you will not have any connection timeouts with the game installed on a SSD ( solid state disk )
If you don´t have any SSD installed in your PC i propose to buy one.
It´s worth the money in every aspect.
Very fast reading/writing in comparison to any HDD.
If you have a M.2 SSD slot on your mainboard you should buy a compatible M.2 SSD card which is in most cases faster than a regular SSD.