Okay, using a microswiss hot end for an example, and that’s a clean photo. They’re all usually about the same anyhow. What’s going on here is a very common mistake to make. the immediate cause is that the heat break (red arrow in the picture) is not screwed on to the heater block tightly enough, and some filament is oozing out the top rather than getting forced out the nozzle.

The solution is to heat it up, clean everything up with a brass brush or something similar. Then remove the nozzle and run filament through while it’s hot, clearing out any gunk that’s built up.

Now, to get it on there tight enough, what you need to do is heat up the nozzle to higher than you normally print at, then tighten it down as tight as it can go while trying very hard to not burn yourself.

You can get the same problem with the nozzle oozing, out (blue arrow) as well, so while you’re running hot, go ahead and put the nozzle back in and get it as tight as you can, too. once it’s done, you can loosen the set screw above the heat break (green arrow. the set screw holds the heat break in place.) and turn the block so it’s more or less aligned with the printer. Let it cool back down and bring it up to temperature and check for leaks again.

and just for the record. everyone here has probably had this happen. I just want to make that clear. please don’t give up. You’ll reach a point where it all makes sense. If you need to step away for a bit, that’s okay, but also, don’t be afraid to come back to it.