make sure the oRings are there

( I suspect you know that already though and assuming its brand new, not second hand? IF second hand it might partly by orings that are wearing thin - can use the flat Kanger Subtank Mini replacement o'rings in place of, a great fix if so)

Lemo 2s MUST have the AC closed when filling
I have found that as soon as i fill it, I turn it upside down, wait for bubbles, then flip backside up and I quickly take a vape like pull out of it even before screwing it back on the mod.

Wicking is super easy.
But the end of the wick naturally is thick like an upside down V. I cut the sides/ends off to its more of a straight line wick and I never lay it on its side, but nor do I do that with any attys for long.

I have 5 and I have never had issues OTHER than the very first day, until I figured out the wick that worked best for me.
Once it worked, it worked perfectly for months.
When it began to leak again, it needed New Orings and worked as well as new

Ooops, HAD 5, I dropped and ruined one.
I have only used 50/50 on mine so far