我用angular5的http post调用短文本相似分析的api 

代码如下，然后一直都提示这个错误信息到底哪里错了啊啊啊啊啊啊啊

            const headers: HttpHeaders = new HttpHeaders().set('Content-Type', 'application/json');
            const params: HttpParams = new HttpParams().set('access_token', '秘钥');
            const body: any = {
                text_1: '123123123123123',
                text_2: '123123123123'
            };
            console.log(body);
            this.http.post('https://aip.baidubce.com/rpc/2.0/nlp/v2/simnet',
                body, 
                { headers, params })
                .subscribe(
                    val => {
                        console.log('相似度为', val['score']);
                    }
                );