what happened to Frost DK

I was using this macro for long time,now the HOW,PS Doesn’t go off. no matter what ability I put in front of PS,PS wont go off after the HB,PS,null
/castsequence reset=target Howling Blast,Plague Strike,null
/castsequence reset=0.3 0,0,Raise Dead
/castsequence reset=0.3 0,Frost Strike
/castsequence reset=0.3 Obliterate
/castsequence reset=target Horn of Winter,Plague Strike