Please help me with this trigger

I'm in trouble with this trigger (I know it's very simple), I want the dummy unit to cast rejuvenation on all friendly units in a range of 500 of the caster, but it casts only on one unit...
Unit - A unit Begins casting an ability
(Ability being cast) Equal to (my abillity)
Unit - Create 1 Dummy unit for (Owner of (Casting unit)) at ((Position of (Casting unit)) facing Default building facing degrees
Unit - Add Rejuvenation (Dummy) to (Last created unit)
For each (Integer A) from 1 to 30, do (Actions)
Loop - Actions
Unit - Order (Last created unit) to Night Elf Druid Of The Claw - Rejuvenation (Random unit from (Units within 500.00 of (Position of (Casting unit))))
Wait 1.00 seconds
Unit - Remove (Last created unit) from the game

Random Unit From Unit Group, why?

you are actually telling that trigger to only cast it to one random unit close

you should do pick every unit in (units in range blah) then order the caster to cast on picked unit

and btw, You should use a unit starts the effect of an ability, and make sure the caster has those weird art stats set to 0 so it can cast on multiple units without delays

I have tried this:
For each (Integer A) from 1 to 30, do (Actions)
Loop - Actions
Unit Group - Pick every unit in (Units within 500.00 of (Position of (Casting unit))) and do (Unit - Order (Last created unit) to Night Elf Druid Of The Claw - Rejuvenation (Picked unit))
But it still casting on only one randon unit.

Are you sure that the casting time of rejuventation is 0 and the dummy unit cast point and cast backswing are 0?