[Plugin: WooCommerce – excelling eCommerce] Check out wont process orders

i have a site which works fine but when i go on to the checkout it loads and then i fill in all the info and then click place order and it just has the little loading circle and i have left it running over night but no luck and i cant find any one else with the same issue as me. please help me

it is on a test server ATM.

https://www.mmdcanvasart.mmdwebdesign.co.uk

please help me

https://www.ads-software.com/extend/plugins/woocommerce/