Error: unable to verify the first certificate

[Sunil Kamble]

hi,
 i am new to mocha, chai,
i am trying to execute below scrip getting error Error: unable to verify the first certificate while executing the script,
getting response as undefined

var chai = require('chai');

var chaiHttp = require('chai-http');

chai.use(chaiHttp);

describe('Get Tenant Id', function () {

  it('get /api/tenants/resolve', function (done) {

    chai.request(apiURL)

      .get(`/api/tenants/resolve`)

      .set({ 'X-Client': `Load Testing ` })

      .query({ 'host': `${tenantHost}` })

      .end(function (error, response) {

        console.log('error', error); // ----->unable to verify the first certificate

        console.log('success', response); // -----> undefined

        expect(response).to.have.status(200);

        // expect(response.status).to.be.equal(200);

        done();

      });

  });

});