You are using Quick.Cart.Add v6.0 or Quick.Cart v6.0? If Quick.Cart.Add v6.0 then you have preinstalled in this script plugin: linkToOrder. Edit core/orders.php and find function: sendEmailWithOrderDetails() and delete that:
I had problem with the function treewod mentioned above. The dashed line was included in the check orders url. When I modified the line to this the problem is gone:
Evertyhing else being the same, today we installed QC Version 5, more precisely we installed a working copy of this form another website. Admin and customer emails work perfectly.
We again tried to install 6.0 & 6.1 ...but email are not being sent.
Are we missing something here? Otherwise, why would a copy of V5 from another website work, but not 6?