Keeving is incredibly difficult to reproduce without having control of the grinding process. CaCL and PME are meant to overcome that lack of control, but sometimes the gap is too large. Don't be discouraged, try again with a new strategy to increase your chances. for example, when possible, try to collect the dregs of a cider-mills pressing. This late juice should have a much higher pectin concentration.
That's how I got this cherry juice keeve I've got going now. Was gonna throw it out but on a whim decided to add some already fermenting apple juice to the sludge of about 200 gallons of cherry to see what would happen.