We can't set up Internet connection sharing

Greetings.

I got a 3G generic windows 8.1 tablet
eSTAR GEMINI HD Intel Quad Core 3G 8.0" - eSTAR - Enjoy Today!
(Quad Core Intel 1,33 GHz processor; Internal Memory Size – 16 GB)

When I connect to my 3G provider (Vodafone) I go to
Connections->Vodafone and the "Share this connection" option is grayed and the message
"We can't set up Internet connection sharing" is red.

Can anyone suggest a solution since I really got the tablet to share my 3G connection to all my devices. I have installed all the relative updates.

Most likely your provider does not allow tethering on the service you have. You need to contact them why you do not have the option to use the device as a hotspot.

Yes I thought of it but I can easily share the connection in an old android phone.

Hi on the phone is that with Vodafone if it is then go back and ask them why it works on that but not on what you have just purchased, as it is up to them to sort it out if they cant then they have to give you a refund.