Why doesnt client.connect accept a full adress - ssl

Question

i am trying to write a piece of code in which the ESP32 connect securely to my api-server and post some sensor data. For this i use the WifiClientSecure library.
Through trial and error i have found out that client.connect(www.myserver.com, 443); works.
But client.connect(www.myserver.com/api, 443); will throw an error.
I have searched the internet for a solution but can't manage to find one.
Full code:
#include <arduino.h>
#include <WiFiClientSecure.h>
const char* ssid = "filled out ssid"; // your network SSID
const char* password = "filled out password"; // your network password
const char* server = "www.server.com/api"; // Server URL
/* use
openssl s_client -showcerts -connect www.howsmyssl.com:443 </dev/null
to get this certificate */
const char* ca_cert = \
"-----BEGIN CERTIFICATE-----\n" \
"MIIF3jCCA8agAwIBAgIQAf1tMPyjylGoG7xkDjUDLTANBgkqhkiG9w0BAQwFADCB\n" \
"iDELMAkGA1UEBhMCVVMxEzARBgNVBAgTCk5ldyBKZXJzZXkxFDASBgNVBAcTC0pl\n" \
"cnNleSBDaXR5MR4wHAYDVQQKExVUaGUgVVNFUlRSVVNUIE5ldHdvcmsxLjAsBgNV\n" \
"BAMTJVVTRVJUcnVzdCBSU0EgQ2VydGlmaWNhdGlvbiBBdXRob3JpdHkwHhcNMTAw\n" \
"MjAxMDAwMDAwWhcNMzgwMTE4MjM1OTU5WjCBiDELMAkGA1UEBhMCVVMxEzARBgNV\n" \
"BAgTCk5ldyBKZXJzZXkxFDASBgNVBAcTC0plcnNleSBDaXR5MR4wHAYDVQQKExVU\n" \
"aGUgVVNFUlRSVVNUIE5ldHdvcmsxLjAsBgNVBAMTJVVTRVJUcnVzdCBSU0EgQ2Vy\n" \
"dGlmaWNhdGlvbiBBdXRob3JpdHkwggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIK\n" \
"AoICAQCAEmUXNg7D2wiz0KxXDXbtzSfTTK1Qg2HiqiBNCS1kCdzOiZ/MPans9s/B\n" \
"3PHTsdZ7NygRK0faOca8Ohm0X6a9fZ2jY0K2dvKpOyuR+OJv0OwWIJAJPuLodMkY\n" \
"tJHUYmTbf6MG8YgYapAiPLz+E/CHFHv25B+O1ORRxhFnRghRy4YUVD+8M/5+bJz/\n" \
"Fp0YvVGONaanZshyZ9shZrHUm3gDwFA66Mzw3LyeTP6vBZY1H1dat//O+T23LLb2\n" \
"VN3I5xI6Ta5MirdcmrS3ID3KfyI0rn47aGYBROcBTkZTmzNg95S+UzeQc0PzMsNT\n" \
"79uq/nROacdrjGCT3sTHDN/hMq7MkztReJVni+49Vv4M0GkPGw/zJSZrM233bkf6\n" \
"c0Plfg6lZrEpfDKEY1WJxA3Bk1QwGROs0303p+tdOmw1XNtB1xLaqUkL39iAigmT\n" \
"Yo61Zs8liM2EuLE/pDkP2QKe6xJMlXzzawWpXhaDzLhn4ugTncxbgtNMs+1b/97l\n" \
"c6wjOy0AvzVVdAlJ2ElYGn+SNuZRkg7zJn0cTRe8yexDJtC/QV9AqURE9JnnV4ee\n" \
"UB9XVKg+/XRjL7FQZQnmWEIuQxpMtPAlR1n6BB6T1CZGSlCBst6+eLf8ZxXhyVeE\n" \
"Hg9j1uliutZfVS7qXMYoCAQlObgOK6nyTJccBz8NUvXt7y+CDwIDAQABo0IwQDAd\n" \
"BgNVHQ4EFgQUU3m/WqorSs9UgOHYm8Cd8rIDZsswDgYDVR0PAQH/BAQDAgEGMA8G\n" \
"A1UdEwEB/wQFMAMBAf8wDQYJKoZIhvcNAQEMBQADggIBAFzUfA3P9wF9QZllDHPF\n" \
"Up/L+M+ZBn8b2kMVn54CVVeWFPFSPCeHlCjtHzoBN6J2/FNQwISbxmtOuowhT6KO\n" \
"VWKR82kV2LyI48SqC/3vqOlLVSoGIG1VeCkZ7l8wXEskEVX/JJpuXior7gtNn3/3\n" \
"ATiUFJVDBwn7YKnuHKsSjKCaXqeYalltiz8I+8jRRa8YFWSQEg9zKC7F4iRO/Fjs\n" \
"8PRF/iKz6y+O0tlFYQXBl2+odnKPi4w2r78NBc5xjeambx9spnFixdjQg3IM8WcR\n" \
"iQycE0xyNN+81XHfqnHd4blsjDwSXWXavVcStkNr/+XeTWYRUc+ZruwXtuhxkYze\n" \
"Sf7dNXGiFSeUHM9h4ya7b6NnJSFd5t0dCy5oGzuCr+yDZ4XUmFF0sbmZgIn/f3gZ\n" \
"XHlKYC6SQK5MNyosycdiyA5d9zZbyuAlJQG03RoHnHcAP9Dc1ew91Pq7P8yF1m9/\n" \
"qS3fuQL39ZeatTXaw2ewh0qpKJ4jjv9cJ2vhsE/zB+4ALtRZh8tSQZXq9EfX7mRB\n" \
"VXyNWQKV3WKdwrnuWih0hKWbt5DHDAff9Yk2dDLWKMGwsAvgnEzDHNb842m1R0aB\n" \
"L6KCq9NjRHDEjf8tM7qtj3u1cIiuPhnPQCjY/MiQu12ZIvVS5ljFH4gxQ+6IHdfG\n" \
"jjxDah2nGN59PRbxYvnKkKj9\n" \
"-----END CERTIFICATE-----\n" ;
/* create an instance of WiFiClientSecure */
WiFiClientSecure client;
void setup() {
Serial.begin(115200);
WiFi.begin(ssid, password);
/* waiting for WiFi connect */
while (WiFi.status() != WL_CONNECTED) {
Serial.print(".");
delay(100);
}
Serial.print("Connected to ");
Serial.println(ssid);
/* set SSL/TLS certificate */
client.setCACert(ca_cert);
Serial.println("Connect to server via port 443");
if (!client.connect(server, 443)){
Serial.println("Connection failed!");
} else {
Serial.println("Connected to server!");
/* create HTTP request */
Serial.print("Waiting for response ");
while (!client.available()){
delay(50); //
Serial.print(".");
}
/* if data is available then receive and print to Terminal */
while (client.available()) {
char c = client.read();
Serial.write(c);
}
/* if the server disconnected, stop the client */
if (!client.connected()) {
Serial.println();
Serial.println("Server disconnected");
client.stop();
}
}
}
void loop() {
}

Answer 1

www.server.com/api is a partial URL. The complete URL will be https://www.server.com/api,
where:
https - This part is called scheme or protocol. HTTPS implies a default TCP port 443 (http mean port 80 by default)
www.server.com - The domain part, can be called also server address.
api- This is a path on the server
WiFiClient, or WiFiClientSecure, is the TCP client, it doesn't know anything about URLs. TCP client recognizes just address, given in form of IP address (192.168.1.20) or FQDN (which is then translated into IP address).
It is easier to use HTTPClient for requesting HTTP resources.
edit: FNDQ->FQDN