Its Not A Problem At All
THIS Is The Reason Why Its Happening
01: Kovu Or Redlines.. (not sure) Are Doing Server Backups And Such (fixing Bugs Or What Ever)
02: Map Is Too Full Of People
03: If Its A downloaded Map It could Be Too Laggy And Have Way To Many Objects Or Such (It Can Get fixed By Changing GLRenderingsystem To DiretX Or What Ever Some Times Even Turning Water Relfection off)
Other Why's It Could Be YOur Computer And Your Choice Of What Version Of The Game You Downloaded, Try Download And Re-install