Looking for experienced Java developer.

I am developing an java web app that integrates with 3rd party API. The thing is that when I trying to send request this persists the following issue. I think this is because of I am calling api in localhost, but I failed to fix it myself. here it is my code OkHttpClient client = new OkHttpClient().newBuilder().build(); MediaType mediaType = [login to view URL]("application/x-www-form-urlencoded"); RequestBody body = [login to view URL](mediaType, "client_id=" + Constants.PAYPAL_CLIENT_ID +"&redirect_uri=" + Constants.PAYPAL_CLIENT_REDIRECT_URL + "&client_secret=" + Constants.PAYPAL_CLIENT_SECRET + "&code=" + code +"&grant_type=authorization_code"); Request request = new [login to view URL]() .url(Constants.API_URL) .method("POST", body) .addHeader("Authorization", "Basic " + B64Encode(Constants.PAYPAL_CLIENT_ID + ":" + Constants.PAYPAL_CLIENT_SECRET)) .addHeader("Content-Type", "application/x-www-form-urlencoded") .build(); Response response = [login to view URL](request).execute(); and the following is exception detail. detailMessage = (String) "[login to view URL]: PKIX path building failed: [login to view URL]: unable to find valid certification path to requested target" Hopefully experienced someone to help me to fix this issue Thanks.