help with cloning!!!!

ok i am new to cloning but have been growing for the past few years. I have a few different strains going i got white widow some strawberry kush and some good shit i found a few seeds in and grew. I bought a t5 ho 4 bulb for cloning i got it about 2 feet above with a heat mat with a few pencles on it so the tray is not directly on the mat. I soaked the 2 inch rockwool cubes for 24 hours with one drop of superthrive per gallon. i took four cutting from each plant at the second or third node down and made sure to cut at a 45 with a node buried in the rockwhool. they are fairly small cuttings about 3 to 4 inches above the rockwool. i put them in the dome for two weeks airing them out each day for a few min. The clones look very healthy and stay green but absoultley no sign of roots after waiting the two weeks i pulled them out of the cubes and there was no roots at all NOTHING. It looks like rot but i only watered the cubes on the original soaking and they stayed moist but not soaking. I cant figure out what the hell im doing wrong and im obsessed with trying to perfect this process. Someone please help! i recently took three of the four t5 ho floros out and left one in and lowered it to 6 inches above dome thats all i can think of. any suggestios???

Hang in their dude. Here is a link thats sure to shed some light on cloning. https://www.rollitup.org/newbie-central/192115-cloning-easy-1-2-3-a.html