Schedule K distribution

I'm filing for a Trust which distributes all income to it's 3 beneficiaries.  In the past, the only income was rental income from a building on a piece of property the Trust owns.  In 2021, we sold the entire property, including the rental building, and had capital gains.  I've indicated 100% of income should go to the beneficiaries but it still shows a tax due for the Trust and I can't figure out why.