As Betty pointed out , there could be a split in the female section. If there is -- unwrap the ferrule wrap, work some epoxy glue into the crack and gently wrap w/ heavy cotton thread or light string. Gently enough that you force the edges together but not so tight that you crush the ferrule out of round. Glue inside the ferrule should be avoided and is easier to remove w/ a little alcohol before it sets than w/ sand paper after.
When the glue sets remove the string, sand clean and wrap the ferrule w/ nylon rod building thread. Wrap from 1/4 inch or so bellow the split up to the end and wrap back for 1/4 inch or so. Finish w/ any epoxy rod finish.
Or -- you might be lucky and the fit is just a bit worn. If so , and if it is not too bad, rub a bit of paraffin wax on the male and see if it is good enough. One caution -- the wax will collect dirt and grit which will chew up the ferrule even worse. Periodic Cleaning of the old wax out of the ferrule is important here.
Or -- it might be so worn that the wax will not be enough. Clean and lightly sand the male ( 600 grit). degrease w/ alcohol, and THINLY coat with a thin coating rod build wrap epoxy. When it is set sand it to fit. The procedure is the same as fitting metal ferrules , which is posted elsewhere on the net, and a much better explanation than I could offer. If you need it, shout out and it will be found.
AgMD