Shimmer Reverb greyed out

Trying to add a shimmer reverb to some patches, and it’s greyed out. If I build a patch from scratch I can use it. Why are some effects greyed out?

You’ve run out of DSP/CPU power on that particular Lane. Try spreading your preset onto other lanes for a more efficient layout.
Lanes 1/2 share half the allotted power, 3/4 the other