Transaction keep giving timeout to update two-related model

[PinKevin]

I develop a code to update the teacher table and user table at the same time. In order for both to success, I need to use transaction. However, my code keeps giving the Knex.js timeout error.

Here's the code
controller

async completeTeacherAfterRegister({ request, response }: HttpContext) {
    const teacherId = request.param('id')
    const payload = await request.validateUsing(updateTeacherValidation)

    const teacherData = {
      id: teacherId,
      ...payload,
    }

    try {
      const teacher = await this.teacherService.completeTeacherInfo(teacherData)

      return this.responseService.successResponse(response, 'Anda berhasil mendaftar', teacher, 201)
    } catch (error) {
      if (error instanceof errors.E_ROW_NOT_FOUND) {
        return this.responseService.failResponse(response, 'Tidak ada guru yang ditemukan', 404)
      }

      return this.responseService.failResponse(response, error.message)
    }
  }

service

async completeTeacherInfo({
    id,
    name,
    nuptk,
    placeOfBirth,
    dateOfBirth,
    gender,
    religion,
  }: CompleteTeacherDataDto) {
    const trx = await db.transaction()

    try {
      let teacher = await Teacher.query({ client: trx })
        .where('id', id)
        .preload('user')
        .forUpdate()
        .firstOrFail()

      if (teacher.name !== null) {
        throw Error('Anda sudah melakukan pendaftaran')
      }
      // teacher.useTransaction(trx)

      await teacher.merge({
        name,
        nuptk,
        placeOfBirth,
        dateOfBirth: DateTime.fromJSDate(dateOfBirth),
        gender,
        religion,
      })

      const user = teacher.user
      // user.useTransaction(trx)

      await user.merge({
        accountStatus: AccountStatus.active,
      })

      await teacher.save()
      await user.save()

      await trx.commit()

      return teacher.serialize() 
    } catch (error) {
      await trx.rollback()

      throw error
    }
  }

The error I got: Knex: Timeout acquiring a connection. The pool is probably full. Are you missing a .transacting(trx) call?

Is there any solution or alternative to this? Thanks in advance