I'm hypothesizing, but probably lack of full powered sun and lack of nutrients probably play in with that. I've not successfully reflowered either.

They won't reflower if you try to grow them again indoors in the usual pebbles and water set-up. They can rebloom if planted out in the garden (in suitable climates). Usually not the first season as they are taking some time building up the bulb energy. If you can successfully grow Mediterranean plants in your climate, then you can grow paperwhites in the ground. Zone 8 for sure and possibly even a zone 7 if with dry, warm summers.

Not all zone 8s are created equal. PWs won't rebloom here because we don’t get sufficient summer heat.