After changing the CustomErrors to mode=off I found out that there is a problem with the shipping calculation method.
Server Error in '/' Application.
Shipping rate computation method could not be loaded
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: Nop.Core.NopException: Shipping rate computation method could not be loaded
Source Error:
Line 217: </div> Line 218: <div class="totals"> Line 219: @Html.Action("OrderTotals", "ShoppingCart", new { isEditable = Model.IsEditable }) Line 220: @if (Model.IsEditable) Line 221: {