It was just traditional mead - raw honey and water. I didn't added anything else. Fermentation started after lot of stirring. I believe raw honey has the yeast and after honey's water content is more than 17%, fermentation starts.
I think I made couple of mistakes like stirring it after the fermentation started, leaving it partially open. I should have used the air lock after fermentation slows down. It does not smell bad, because mold is just on the sides of carboy.
Also I left good amount of space in the carboy, thereby exposing the area for mold. I should have filled it almost to the neck.