Cannot add more than one variant

-- HikaShop version -- : 2.6.1
-- Joomla version -- : 3.4.8
-- PHP version -- : 5.5.30
-- Browser(s) name and version -- : safari 9.0.2
-- Error-message(debug-mod must be tuned on) -- : None

I have set up 3 characteristics with each characteristic having 2 variants. Everything has been working as expected until this evening. I am unable to have more than one variant per characteristic. When I select one of the characteristics and choose one of the variants, it gets added. But, when I try to add the second variant, it overwrites the first variant. I have no idea what could have been changed. But, I really need your help on this.

I just reinstalled the latest version of Hikashop and it did not help. Same problem.

My apologies. The error was mine and had nothing to do with Hikashop. It is resolved now.