Try using friend instead of ally.
AC Boost; AURA: 10 friend; AC Boost; AC: 6
Make sure the enemies are set to foe/hostile and not friendly.
- ally = PC's and all others matching their faction.
- friend = PCs and friendly NPCs
- foe = hostile NPCs
- neutral = neutral NPCs (if supported by your Aura Effects version)
- self = only the caster
- notself = everyone except the caster
- all = literally everyone

