Where is it leaking? If it screws into the housing and that not damaged ie cracked, them wrap the threads on the male connector with a couple of turns of PTFE tape. Put the tape on clockwise with the connector facing you.
If its the connector that's leaking, then the chances are that you can sort it with a new rubber o ring. You can get them of ebay (hozelok o rings) or probably form B & Q or your local garden center.