Why does enzyme wrapper doesn't find a button?

I have these dev dependencies installed:

"devDependencies": {
    "enzyme": "3.11.0",
    "enzyme-adapter-react-16": "1.15.6",
    "jest-enzyme": "7.1.2"
  },

This is my test code:

const onClickSpy = jest.fn();
  const wrapper = shallow(
    <MessageItem
      message=
      deleteMessageFromTable={onClickSpy}
    />
  );

I have a wrapper wich contains the following:

<div class="MuiPaper-root-7 MuiPaper-elevation8-17 MuiPaper-rounded-8 MuiCard-root-6">
  <div class="MuiCardContent-root-34">
    <p class="MuiTypography-root-35 MuiTypography-body1-44 MuiTypography-colorTextSecondary-68 MuiTypography-gutterBottom-62 MessageItem-title-5">
      testmessage
    </p>
  </div>
  <div class="MuiCardActions-root-71">
    <button
      class="MuiButtonBase-root-100 MuiButton-root-74 MuiButton-text-76 MuiButton-flat-79 MuiButton-sizeSmall-97 MessageItem-cardclearbutton-1 MuiCardActions-action-73"
      tabindex="0"
      type="button"
      id="button-messageitem-1"
    >
      <span class="MuiButton-label-75">Clear</span>
    </button>
  </div>
</div>

Why does wrapper.find("#button-messageitem-1"); don't find the button?

I also tried wrapper.find("button"); and nothing, no matter what I always get the error message: Method “html” is meant to be run on 1 node. 0 found instead..

Thank you for your support.