Fetch-Mock Error. No fallback response defined for POST

Question

I need to test an asynchronous function (redux thunk) in jest. To do this, I decided to use fetchMock. But I'm having problems. The test ends successfully but I get an error from fetch

'fetch-mock: No fallback response defined for POST to http:// *Link* /tmo/rest/user'

Testing block in jest:

it('test: AuthMethod', async () => {
    fetchMock.mock(Link, 200);
    fetchMock.getOnce('/tmo/rest/user', {
      body: JSON.stringify(body),
      method: 'POST',
      headers: header,
    });

    store.dispatch(AuthMethod()).then(() => {
      let expectedActions = [
        {
          type: FETCH_AUTH_SUCCESS,
          payload: data,
        },
      ];
      expect(store.getActions()).toEqual(expectedActions);
    });

    let value = store.getState();
    console.log(value);
  });

Fetch-Mock Elements:

body:

const body = {
  login: login,
  password: password,
  deviceSerialNumber: '1111111',
  currentAppVersion: AppVersion,
  currentDateTime: time,
};

headers:

const header = {
  Accept: 'application/json',
  'Content-Type': 'application/json',
};