[Help]i need some help here..

hi all..anyone know how to fix XP skill bug??
my server cannot doing XP skill & xp bar always zero..all player..including me..cannot xp..and i have try using commmand /xp but still cant use..already search in forum..but found zero..plss help me..TQ

Hate to point out the obvious but do you have an xp skill equipped? like starsword, rage something? as ur xp skill wont go off without learning an xp skill