Connecting ESP8266 with HTTPS Python server: ESP not connecting and giving BearSSL error code that server name is bad

Question

#include <ESP8266WiFi.h>
#include <WiFiClientSecure.h>

#ifndef STASSID
#define STASSID "ssid"
#define STAPSK  "pwd"
#endif

WiFiClientSecure client;

const char* ssid = STASSID;
const char* password = STAPSK;
const char* host = "server ip";
const int httpsPort = 443;

// DigiCert High Assurance EV Root CA

static const char trustRoot[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
MIIDZzCCAk8CFC6I3N+ayMvUYtM5fV3dgVter3/HMA0GCSqGSIb3DQEBCwUAMHAx
...
...
5yZi0b12t0nRhP9/nfqjrq18qQvuNpFMkEZoX55TU1j+6FTIHlcBSBEzAwRlcy6z
ayyQAen4YGq3fMk=
-----END CERTIFICATE-----
)EOF";

X509List cert(trustRoot);

const char client_cert[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
MIIDZzCCAk8CFEHOqlzoEw8VZ9UyBUh+Pg9ZGT0cMA0GCSqGSIb3DQEBCwUAMHAx
...
...
K6VmXQciQQuk7V0i75CyxevY9GVDVHs0hpoG7kfXVUVnBo+wQII7p7tEbcJBiQrG
tmQix+1gLmYmsH4=
-----END CERTIFICATE-----
)EOF";

/*-----------------------------------------------------------------*/

const char client_private_key[] PROGMEM = R"KEY(
-----BEGIN PRIVATE KEY-----
MIIEwAIBADANBgkqhkiG9w0BAQEFAASCBKowggSmAgEAAoIBAQC5UPJy4qfYeFzd
...
...
cajJThoAW7ihH96fZW7vK0ejSeAxwBgorwzbhWvEORt6be5j2eUycT5q6eOYGXCg
IbCUotZgJRw81XO0uNeYCFyClwM=
-----END PRIVATE KEY-----

)KEY";

void setup() {
  Serial.begin(115200);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP())

  // Set time via NTP, as required for x.509 validation
  configTime(3 * 3600, 0, "pool.ntp.org", "time.nist.gov");
  Serial.print("Waiting for NTP time sync: ");
  time_t now = time(nullptr);

  while (now < 8 * 3600 * 2) { 
    delay(500);
    Serial.print(".");
    now = time(nullptr);
  }

  Serial.println("");

  struct tm timeinfo;

  gmtime_r(&now, &timeinfo);

  Serial.print("Current time: ");
  Serial.print(asctime(&timeinfo));
  Serial.print("Connecting to ");
  Serial.println(host);

  client.setTrustAnchors(&cert);
  X509List serverCertList(client_cert);
  PrivateKey serverPrivKey(client_private_key);
  client.setClientRSACert(&serverCertList,&serverPrivKey);
  if (!client.connect(host, httpsPort)) {
    Serial.println("Connection failed");
    Serial.print(client.getLastSSLError());
    //delay(1000);
  } else {}
  
  //client.connect(host, httpsPort);
  //String url = "/repos/esp8266/Arduino/commits/master/status";
  //Serial.print("Requesting URL: ");
  //Serial.println(url);
  //client.print("Hello from esp8266");
  /*client.print(String("GET ") + url + " HTTP/1.1\r\n" +
               "Host: " + host + "\r\n" +   
               "User-Agent: BuildFailureDetectorESP8266\r\n" +
               "Connection: close\r\n\r\n");*/

  //Serial.println("Request sent");
 
  while (client.connected()) {
    String line = client.readStringUntil('\n');
    if (line == "\r") {
      Serial.println("Headers received");
      break;
    }
  }

  String line = client.readStringUntil('\n');

  /* if (line.startsWith("{\"state\":\"success\"")) {
    Serial.println("esp8266/Arduino CI successfull!");
  } else {
    Serial.println("esp8266/Arduino CI has failed");
  }*/

  Serial.println("Reply was:");
  Serial.println("==========");
  Serial.println(line);
  Serial.println("==========");
  Serial.println("Closing connection");
}

void loop() {
}

I tried to load both server and client certificates and a private key to run, but it is not connecting to the server. I am also attaching the logs of BearSSL:

Wifi connected IP address:
192.168.34.12

Waiting for NTP time sync: 
Current time: Tue Oct 27 04:06:24 2020

Connecting to 192.168.15.123(server ip) 
Connection failed

Error code:56

Answer 1

You are passing an IP address as a const char* to client.connect(), but that function expects an array of 4 bytes for IP addresses; it now thinks it is getting a URL which it will try to resolve to an IP address (and it will fail).

If you declare either IPAddress host(192, 168, 15, 123); or const char* host = "hostname"; then client.connect(host, httpsPort); will work; it will not understand this:

const char* host = "192.168.15.123";