Hey there.

The description of your steps suggests you didn't do something wrong, your dose is also certainly not small.

(consider extending the reaction time from 20 to 25-30 minutes, however 20 minutes should also work)

I can think of two different possibilities, one is i am not sure about how well a ball consisting of zeolite microparticles stuck together by THC would dissolve in the stomach, perhaps it does not partially/fully dissolve leaving THC molecules mechanically trapped in the zeolite "plaster" piece , this is just an anecdotal speculation, however, you could test this by dissolving the zeolite/THC plaster in a small amount of ethanol and consuming this instead.

The other is, i suppose you have tried edible THC before, but if not, be aware that a small percentage(~2%) of the population is "immune" to oral THC or need extremely high doses to feel anything, the gene CPY2C9 is linked with the enzyme that metabolizes THC, if you have a rare subtype of that gene, the process could be too efficient, metabolizing THC to a waste product before the intoxicating metabolite can enter the bloodstream.