护照检查真实，但无法得到任何回复

I use laravel-passport to get the token(/oauth/token), the mode is password, the validation is passed, and oauth_access_tokens is stored in the record, but the postman has not received any response.

 /**
     * @param $username
     * @return Model|\Illuminate\Database\Query\Builder|object|null
     */
    public function findForPassport($username) {
        $user_info = $this
            ->select([
                'password',
                'no'
            ])
            ->where('email', $username)
            ->first();

        return $user_info;
    }

    /**
     * @param $password
     * @return bool
     */
    public function validateForPassportPasswordGrant($password)
    {
        return $this->attributes['password'] == md5($password . md5( $this->attributes['no']));
    }




 'api' => [
            'driver' => 'passport',
            'provider' => 'accounts',
        ],

  'accounts' => [
            'driver' => 'eloquent',
            'model' => App\Entities\User::class,
        ],

have no error message.