API Error after upgrading to 2026.3

After upgrading to 2026.3 my esp8266 related sonsors are not available anymore in homeassistant.
In the log I found the following error:

WARNING Can't connect to ESPHome API for esp-aussentemp @ 10.10.10.10: esp-aussentemp @ 10.10.10.10: EOF received (SocketClosedAPIError)

Stepping back to 2026.2.4 immediately solves the problem (and the data is available again in HASS).

Configuration yaml is as follows:

esphome:
  name: esp-aussentemp

esp8266:
  board: nodemcu

# Enable logging
logger:
#  level: NONE
#  hardware_uart: UART0_SWAP

# Enable Home Assistant API
api:
  encryption:
    key: "..."

ota:
  platform: esphome
  password: "..."

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  min_auth_mode: WPA2
  power_save_mode: light
  manual_ip:
    static_ip: 10.10.10.10
    gateway: 10.10.10.1
    subnet: 255.255.255.0
  use_address: 10.10.10.10

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Esp-Aussentemp Fallback Hotspot"
    password: "..."


captive_portal:


# Serial for RG-9
uart:
  #rx_pin: GPIO3
  #tx_pin: GPIO1
  rx_pin: GPIO13
  tx_pin: GPIO15
  baud_rate: 9600

#dallas:
one_wire:
  - platform: gpio
    pin: GPIO2

sensor:
  #- platform: dallas
  - platform: dallas_temp
    address: 0xd73cd2e381a47428
    name: "Aussentemperatur"

  - platform: adc
    pin: VCC
    name: "VCC Voltage"

  - platform: hydreon_rgxx
    model: "RG_9"
    update_interval: 30s
    moisture:
      name: "rain"
#    temperature:
#      name: "RG9_temp"

binary_sensor:
  - platform: hydreon_rgxx
    too_cold:
      name: "too cold"
    lens_bad:
      name: "lens bad"

any thoughts?

greetings,
Markus

I don’t see the error but I am having issues with logging not showing API interactions and things like binary sensors not updating.

Was there some mention of serial ports in the breaking changes for the last update?

There is already a fix for this merged. Fix will be in the next update.

See: ESP8285 won't connect to wifi since last update - #3 by bdraco

1 Like

hmmm … I’m not a programmer, but the linked article is about failed wifi connection. wifi connection is not the issue in my case. The ESP is reachable using wifi all the time.

If you click on the issue that PR fixes you will see:

https://github.com/esphome/esphome/issues/14999