Golang API调用失败

I am trying to call a restful API using a certificate. The pem file I have is of the format:

-----BEGIN RSA PRIVATE KEY-----
    data is here
-----END RSA PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
    data is here
-----END CERTIFICATE-----
-----BEGIN CERTIFICATE-----
    data is here
-----END CERTIFICATE-----

The code that i am using is

//creating the certificate for call
caCert, err := ioutil.ReadFile("certFil.pem")
if err != nil {
       log.Fatal(err)
}


caCertPool := x509.NewCertPool()
caCertPool.AppendCertsFromPEM(caCert)

client := &http.Client{
       Transport: &http.Transport{
              TLSClientConfig: &tls.Config{
                     RootCAs:      caCertPool,
              },
       },
}

//end of creating the certificate for call

//creating the body for call
url := "https://example.com:11215/myuri/path1/path2"
fmt.Println("URL:>", url)

var jsonStr = []byte(`{
  "My JSON" 
} `)

req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonStr))
req.Header.Set("Accept", "application/json;v=3")
req.Header.Set("Cache-Control", "no-cache, no-store")
req.Header.Set("Connection", "Keep-Alive")
req.Header.Set("User-Agent", "HttpClient")
req.Header.Set("Content-Type", "application/json;v=3")

//client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
       panic(err)
}
defer resp.Body.Close()

When I run this code I get an exception:

x509: certificate is valid for fake.com, not example.com

Can you please help me solve this issue?