Common Causes

📡

5 GHz Wi-Fi Only

The ESP32 supports only 2.4 GHz Wi-Fi. If your router does not broadcast a 2.4 GHz signal, the ESP32 cannot detect or join the network.

🔒

WPA3-Only Security Mode

WPA3-SAE support is available on ESP32 variants (e.g., S2, S3, C3, C6) when using ESP-IDF v4.4+ or Arduino-ESP32 core v2.0+. Legacy ESP32 boards or firmware may lack WPA3 support. For compatibility, avoid configuring the router to WPA3-only mode unless the ESP32 firmware explicitly supports it.

⚙️

Incompatible Channel or Bandwidth Settings

ESP32 may struggle with certain high channel numbers or non-standard bandwidth settings, especially in congested Wi-Fi environments.

🌐

AP Isolation (Client Isolation)

When enabled, AP isolation prevents devices on the same network from communicating, which can block ESP32 traffic or OTA updates.

Symptoms

ESP32 Fails to Connect Despite Correct Credentials

The device repeatedly attempts to connect but fails or disconnects immediately after authentication.

ESP32 Not Discovering Network

The ESP32 cannot find your SSID, especially if it’s only available on the 5 GHz band or hidden.

Unreachable After Connection

ESP32 connects and gets an IP address, but is not reachable from other devices on the same Wi-Fi due to isolation settings.

Solutions

Ensure 2.4 GHz Wi-Fi is Enabled

Make sure your router broadcasts a 2.4 GHz network with a unique SSID that the ESP32 can discover and join.

Enable Mixed WPA2/WPA3 Mode

In your router settings, select a mixed-mode security profile (WPA2/WPA3) to ensure ESP32 compatibility.

Use Standard Wi-Fi Channels (1–11)

Stick to common 2.4 GHz channels and avoid channel bonding or overly aggressive bandwidth modes that can confuse the ESP32.

Disable AP Isolation or Client Isolation

Turn off client/AP isolation in your router’s advanced settings to allow device-to-device communication on the same network.

More Details

⚙️ ESP32 Wi-Fi Settings Incompatible with Router #

If your ESP32 is failing to connect — despite correct credentials — the issue may lie not with your code, but with your router's settings.

Some router configurations are incompatible with ESP32 hardware, especially when using newer features like WPA3 or 5 GHz Wi-Fi. Adjusting these settings can often resolve otherwise confusing connection failures.

Common Scenarios #

ESP32 endlessly attempts to connect but never gets an IP
Serial monitor shows connection loops or WL_NO_SSID_AVAIL
The network isn’t discovered at all by the ESP32
You can't ping or send data to the ESP32 once it's connected

Incompatible Settings to Watch Out For #

📡 5 GHz Wi-Fi Only #

The ESP32 only supports 2.4 GHz Wi-Fi. If your router is set to 5 GHz only or uses the same SSID for both bands without dual-band support, the ESP32 won’t even see the network.

Fix: Enable 2.4 GHz with a separate SSID to ensure ESP32 can connect.

🔒 WPA3-Only Networks #

ESP32 boards do not support WPA3 by default unless using newer hardware (e.g., S2/S3/C3) with updated firmware (ESP-IDF v4.4+ or Arduino core v2.0+). If your router is set to WPA3-only, unsupported ESP32 devices may fail to connect or show generic connection errors.

Fix: Switch to WPA2/WPA3 mixed mode in your router's wireless security settings.

⚙️ Non-Standard Channel or Bandwidth #

The ESP32 is most stable on channels 1–11 in the 2.4 GHz band. Unusual bandwidth settings (like 40 MHz or dynamic channel selection) can cause erratic behavior.

Fix: Set the channel manually to something safe (e.g., 6), and disable aggressive bandwidth options.

🌐 AP (Client) Isolation #

Some routers enable “AP Isolation” or “Client Isolation,” which prevents devices on the same Wi-Fi network from communicating with each other. This breaks ESP32 functionality such as OTA updates, local servers, or debugging via mobile apps.

Fix: Disable AP Isolation in your router’s advanced wireless settings.

How to Confirm the Issue #

Use a smartphone to connect to the same SSID — check if it's WPA3 or 5 GHz only
Log into your router’s admin panel and inspect the wireless configuration
Run a Wi-Fi scan in the ESP32 sketch:

int n = WiFi.scanNetworks();
for (int i = 0; i < n; i++) {
  Serial.println(WiFi.SSID(i));
}

If your network doesn’t show up, it’s likely hidden, 5 GHz, or isolated.

Summary #

Wi-Fi problems with ESP32 often stem from router settings rather than code bugs. Make sure the network is 2.4 GHz, uses WPA2, and doesn’t isolate clients. A few quick changes in your router’s admin panel can restore reliable connectivity.

ESP32 Wi-Fi Settings Incompatible with Router