Board is not working with Kamstrup Multical 603

[teunaldo]

I have the board let build by JLC-PCB.com but I don't get a reaction from Kamstrup. I use a WEMOS D1 Mini v3.1.0

The code I use is:

esphome:
  name: dsmr-kamstrup-meter2
  friendly_name: dsmr-kamstrup-meter2

esp8266:
  board: esp01_1m
# Enable logging
logger:
  level: DEBUG  # Logging costs performance, switch to DEBUG when needed only
  baud_rate: 0 # disable logging over uart (would use up a HW uart)
# Enable Home Assistant API
api:
  encryption:
    key: "***************************************"

ota:
  - platform: esphome
    password: "***************************************"

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Dsmr-Kamstrup-Meter2"
    password: "***************************************"

captive_portal:
    
# Web server for local access
web_server:
  port: 80
uart:
    id: uart_bus
    rx_pin: GPIO13
    tx_pin: GPIO15
    baud_rate: 1200
    data_bits: 8
    parity: NONE
    stop_bits: 2

 sensor:
   - platform: kamstrup_kmp
     heat_energy:
       name: Heat Energy
     power:
       name: Heat Power
     temp_diff:
       name: Heat Temperature Difference
     flow:
       name: Heat Flow
       custom:
       - name: Custom Heat Energy
         command: 0x003C
       - name: Custom Heat Power
         command: 0x0050
     update_interval: 20s

When I look with a phone into the LED, I see a purple glow blinking when it requests for information so that looks fine. I had this in the past working on my Rpi with a IR eye, so it looks like the Kamstrup is doing fine. (https://github.com/matthijsvisser/kamstrup-402-mqtt)

The D1 mini is mounted towards the pins that need to be used for this. I also tried to connect the pins that are on the place of D13 and D14 (+3.3v+GND) to an ESP32, but that does not work either.