[Flutter] How to solve Flutter CERTIFICATE_VERIFY_FAILED error while performing a POST request?

I am sending a post request in Dart. It is giving a response when I test it on API testing tools such as Postman. But when I run the app. It gives me the following error:-

E/flutter ( 6264): HandshakeException: Handshake error in client (OS Error: E/flutter ( 6264): CERTIFICATE_VERIFY_FAILED: unable to get local issuer certificate(handshake.cc:363))


Here is my code of the function -

Future getAccessToken(String url) async {

try {
http.post('url',
body: {
"email": "xyz@xyz.example",
"password": "1234"
}).then((response) {
print("Reponse status : ${response.statusCode}");
print("Response body : ${response.body}");
var myresponse = jsonDecode(response.body);
String token = myresponse["token"];
});
} catch (e) {
print(e.toString());
}


Here's the full error body:

E/flutter ( 6264): [ERROR:flutter/shell/common/shell.cc(184)] Dart Error: Unhandled exception: E/flutter ( 6264): HandshakeException: Handshake error in client (OS Error: E/flutter ( 6264): CERTIFICATE_VERIFY_FAILED: unable to get local issuer certificate(handshake.cc:363)) E/flutter ( 6264): #0 IOClient.send (package:http/src/io_client.dart:33:23) E/flutter ( 6264): <asynchronous suspension> E/flutter ( 6264): #1 BaseClient._sendUnstreamed (package:http/src/base_client.dart:169:38) E/flutter ( 6264): <asynchronous suspension> E/flutter ( 6264): #2 BaseClient.post (package:http/src/base_client.dart:54:7) E/flutter ( 6264): #3 post.<anonymous closure> (package:http/http.dart:70:16) E/flutter ( 6264): #4 _withClient (package:http/http.dart:166:20) E/flutter ( 6264): <asynchronous suspension> E/flutter ( 6264): #5 post (package:http/http.dart:69:5) E/flutter ( 6264): #6
_MyLoginFormState.getAccessToken (package:chart/main.dart:74:7) E/flutter ( 6264): <asynchronous suspension> E/flutter ( 6264): #7
_MyLoginFormState.build.<anonymous closure> (package:chart/main.dart:64:29)

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