Please help! My babies are dying! Please help or all will be dead!

I'm having a problem with my newly sprouted seeds. Please help me they are DYING!

I'm just worried because I planted 5 seeds a few days ago and got them all to sprout in rockwool cubes and placed in a tray with a dome. Shortly after growing an inch and a half the stems of 3 of the new sprouts started to become weak. Two of them are dead now so I decided to pick up the cubes of the remaining 3 to check if the roots grew out under the cubes and they did. Two of the 3 look good, they are nice and green and they have leaves starting. The other one looks a little stunted but still green.

I just don't understand why they we're thriving at first and now they are stunting and dying.

I thought at first the two started to die because it might be my 60 watt 6400k bulb that was only 6-7 inches away so I moved it up to 11 inches. (It did get a little warm and could dry out the cubes if I left them for longer then 10 hours and didn't mist the dome but not anything like a hps/mh)

Then the first one died so I thought maybe they weren't getting air exchange because of the dome. So I opened the little holes in the dome to let some air in while I was away.

Then the second one died. So then yesterday I decided to check the bottom of the remaining live cubes and all but one of them has a root poking throuh. So now I decided that I just need to get the remaining live cubes into my mini dwc in hopes to keep them alive.

Did the roots just start growing out in the tray for to long?

Or did misting them twice a day and keeping the cubes just wet enough in the dome so they didn't dry out cause over watering? (I adjusted all water to 5.5-5.8 ph.)

I really ned help, thank you all for constructive feedback. I really need the help or I fear more will die! Please help.

Pics would help. Did you crack the vents a little at a time? Was the water in the tray cold at first? Was the light on 24/0?

What is damping off?

I will include a picture shortly.

The water in the tray should have never dropped below 66 Even at night my temps don't really go below 66. Should I get a heating mat for them?

Take the Light out..give it 3 or 4 days.. I just had this happen to me a month and a half ago...Just Take it easy.. I know what people will say is right but Im Telling you I JUST HAD THIS PROBLEM Occur with my babies..I took the light off and let the babies grow a bit(UnderHumidifier)

Thank you so much. Should I just keep them in the dark for 48hrs and then put them on a regular light schedule again? I'm also gonna put them on 18/6 when I give them light again, I feel it stresses the plants so much less.

This is the aftermath, does anyone think the one's in the back will make it?

And one of the good ones is growing sideways, will it go back to normal or should I try and give it some support?

Thanks for the help everyone!

You need to put the light closer to the plants they are strechinq .