Hello Everyone

I am working on an assembly, and it has been years since I had to do anything beyond designing a simple part in solidworks. I have most of the assembly done, however I am having problems getting a couple of mates to work. I am trying to get the circled pins to attach to the circled holes in the attached picture. However whenever I try to mate them it cancels out the other mates. It "SHOULD" be able to attach there with the mechanical joints I have put in.