I am trying to modify a layout where I have to extend a bottom layer wire to connect to a pad. When I am trying to do so, the wire is not attaching to pad. I am also getting err16: two tracks too close. What could be the problem? I had to replace the footprint of a connector and re-route the wires. Since I am new to KiCAD (just two days old!), pls. consider giving me step by step instructions on the topic.