ESP32 TCP Client Connection Refused

In this tutorial, you'll learn about ESP32 TCP Client Connection Refused. We cover key concepts, practical examples, and best practices.

The Problem

ESP32 TCP client cannot connect to a TCP server — connection refused or timeout.

Quick Fix

Wrong

WiFiClient client;
client.connect("192.168.1.100", 5000);
client.print("Hello");

[E][WiFiClient.cpp:315] connect(): Connection refused errno 111

Right

WiFiClient client;
if (client.connect("192.168.1.100", 5000, 10000)) {
  client.println("Hello TCP Server");
  while (client.connected()) {
    if (client.available()) {
      String resp = client.readString();
      Serial.println(resp);
    }
  }
} else { Serial.println("Connection failed"); }

Connected to server
Server response: ACK received

Prevention

Check return value of connect(). Set a timeout (3rd parameter). Verify server is reachable. Check firewall rules. Ensure port is correct.

DodaTech engineers apply these same patterns across Doda Browser, DodaZIP, and Durga Antivirus Pro for production IoT reliability.

FAQ