Yeah, I think what you have going on is a lot of cold solder joints. With your iron as hot as it will go, try holding it against the terminal strip at terminal 1, then count to ten. Watch as the solder melts a little first and balls up, then some time later it will just flatten out against the terminal strip and flow around your wires. This is what is required to get a good solder joint with good connectivity, and after that flowing has occurred, you can lift your iron off and notice that the joint will harden up and be shiny.
Do resist the temptation to add more solder unless absolutely necessary. As you add more solder, you are increasing the load on your soldering iron, and if you get a big enough ball of solder, the iron will no longer be able to keep it melted and you will end up with a bit of a mess.
-PB