Preview build — page text is a draft awaiting human review. Code badges come from real compiles. The flasher is real but not yet hardware-tested; the Playground is still a preview.
Get Started
Wi-Fi · ESP32

Fix: ESP32 Wi-Fi not connecting (stuck on WL_DISCONNECTED)

WiFi.begin() never connects. Check 2.4 GHz band, SSID/password, router security mode, signal and power, in that order.

ESP32ESP32-S3ESP32-C3ESP8266Updated 31 Oct 2026

Community draft — report a mistake

What you see

OutputOutput
Connecting to MyHome-5G
..............................
[  15200][W][STA.cpp:537] connect(): STA disconnected, reason: 201 (NO_AP_FOUND)
Failed to connect after 15 s

When an ESP32 refuses to join Wi-Fi, the cause is almost always the network, not the board: a 5 GHz-only SSID, a typo in the password, or a router security mode the core does not support.

Print the disconnect reason — it tells you which of these it is.

Quick fix — try in order

  1. 1

    Use the 2.4 GHz network

    ESP32 and ESP8266 radios are 2.4 GHz only (the ESP32-C5 is the exception). If your router has one SSID for both bands, create a separate 2.4 GHz SSID.

  2. 2

    Check SSID and password exactly

    They are case-sensitive. Copy them from the router page; watch for trailing spaces.

  3. 3

    Read the disconnect reason

    Core 3.x logs it: 201 NO_AP_FOUND = wrong SSID or band; 15 / 202 auth fail = wrong password or security mode.

  4. 4

    Set WPA2 (or WPA2/WPA3 mixed)

    Pure WPA3 networks can fail on older cores. Mixed mode works with everything.

  5. 5

    Check signal and power

    Weak signal and brownouts during connect look the same. Move closer and use a good supply.

Why it happens

Why does it work on my phone?

Phones support 5 GHz; the ESP32 only sees 2.4 GHz. A 5 GHz-only SSID is invisible to it, giving NO_AP_FOUND.

Hidden SSID or MAC filtering

Hidden networks need the exact name; MAC filtering blocks unknown devices — add the ESP32’s MAC (WiFi.macAddress()).

Power dips during connect

Wi-Fi calibration draws current peaks. If the board resets while connecting, see brownout detector.

ADC2 pins and Wi-Fi

Unrelated to connecting, but analogRead on ADC2 pins stops working once Wi-Fi is on — see ADC2 with Wi-Fi.

Board-specific notes

ESP8266: Same 2.4 GHz rule. WiFi.status() returning WL_NO_SSID_AVAIL means the SSID was not found.

↑↓ to move · Enter to open