Unable to connect to the database Nest js e2e test with gql

I have a question. Now am working on gql + test e2e (i'm very new for test e2e) How can I test create mutaion

here is my categoryProduct.e2e-spec.ts

describe('AppController (e2e)', () => {
  let app: INestApplication
  let apolloClient: ApolloServerTestClient

  beforeEach(async () => {
    const moduleFixture: TestingModule = await Test.createTestingModule({
      imports: [AppModule],
    }).compile()

    app = moduleFixture.createNestApplication()
    await app.init()

    const module: GraphQLModule = moduleFixture.get<GraphQLModule>(
      GraphQLModule,
    )
    // apolloServer is protected, we need to cast module to any to get it
    apolloClient = createTestClient((module as any).apolloServer)
  })

  const createCategoryProductObject = {
    name: 'testData',
  }
  const createCategoryProductQuery = `mutation {
    createCategoryProduct(input: ${createCategoryProductObject}) {
      name
    }
  }`

  it('getAllCategoryProduct', async () => {
    const { query } = apolloClient
    const result: any = await query({
      query: gql`
        query {
          getAllCategoryProduct {
            name
            id
          }
        }
      `,
    })
    console.log(result)
    expect(result)
  })
  it('createCategoryProduct', async () => {
    const { mutate } = apolloClient
    const result: any = await mutate({
      mutation: gql`
        ${createCategoryProductQuery}
      `,
    })
    expect(result)
  })
})
})

As you see in my getAllCategoryProduct I console.log(result) I get the right result and everything work fine but in createCategoryProduct I get an error

Unable to connect to the database. Retrying (1)...
AlreadyHasActiveConnectionError: Cannot create a new connection named "default", because connection with such name already exist and it now has an active connection session.

not sure why cannot connect database