I think you're talking about the plug that goes into the machine coming apart. You can't fix the standard plug it thing, but there's a replacement part available that can be dissassembled and put back together again: link to part
/edit: I ignored the red message about reviewing the post... but if it's the entire plug coming out of the machine, it's like woodguy said, make sure it's properly locked (which can be a bit stiff when new)