Okay so I am trying to build a mining base on the Mun. I have already added two modules to my base and I am now trying to add my third. Everything went as usual. I built my module, added a skycrane, test said skycrane on Kerbin, build rocket to send it to the mun, and finally go to the mun. But when I finally got to add the module, the stubborn docking ports won't connect. I wasted what was probably more than an hour trying to connect the ports to no avail, even though i could get it to align perfectly. Getting desperate, I sent a probe to connect some RCS thrusters at the back, but that was just another hour wasted as it still doesn't connect. I've tried everything, even gravity hack. What's wrong, how do I fix this?