joomla get stuck on step 1 of checkout

-- url of the page with the problem -- : kt-sportsfrance.eu/boutique/checkout
-- HikaShop version -- : 3.3.0
-- Joomla version -- : 3.5.1
-- PHP version -- : 5.6.33
-- Browser(s) name and version -- : all
-- Error-message(debug-mod must be tuned on) -- : page times out

Hi

I wrote this topic earlier using a new registered user as I had forgotten this user. I have purchased the subscription for Hikashop and upgraded to 3.3.0

The checkout page doesn't respond correctly. When the user selects to make the payment (to Paypal) the page stays in a loop at Step 1. Eventually it refreshes to show:
Service Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
Additionally, a 503 Service Unavailable error was encountered while trying to use an ErrorDocument to handle the request.
Can you assist so that we can get users purchasing again
Thanks

Hello,

We'll continue through that thread :
www.hikashop.com/forum/checkout/893918-c...n-step-1.html#288617

Thank you.