If using a small iron, it takes a while to heat the connector up to the point where it will take solder. It's acting like a heat sink, and so is anything you are using to hold it (pliers, etc). I use a set of
helping hands to hold the connector - the clips are metal so they won't melt, yet small enough to prevent too much heatsinking.
Even though a small iron works, you'll have an easier time with a higher power iron, especially if you are impatient.
