MySensors - USB gateway - No devices could be setup

Hi everyone.
I have a problem with connect MySensors gateway over USB. Home Assitant is installed on docker (RPi 3B+) and Arduino Mega is connected via USB. I have checked the port using: ls /dev/ttyACM* command. I am using this script:

I tried add baudrate 115200, but nothing changed.

Logs:
2020-07-14 19:39:27 ERROR (MainThread) [homeassistant.components.mysensors] No devices could be setup as gateways, check your configuration
2020-07-14 19:39:27 ERROR (MainThread) [homeassistant.setup] Setup failed for mysensors: Integration failed to initialize.

configuration.yaml:

mysensors:
  gateways:
   - device: '/dev/ttyACM0'
     persistence_file: '/mysensors.json'
     baud_rate: 115200
  optimistic: false
  persistence: true
  retain: true

On domoticz everthink is working fine.

Read this post, specially point 11:

In yaml, indentation is very important, at first sight your gateways: line needs to have 2 spaces in front, but impossible to tell the way you posted.

Thank you for reply. I corrected the post, sorry, my mistake.
I know about spaces, i think they are fine in the code.

I found the solution, i didn’t add ttyACM0 device in docker config. But i have another problem :confused:
2020-07-14 22:35:35 WARNING (MainThread) [homeassistant.components.mysensors.gateway] Gateway /dev/ttyACM0 not ready after 15.0 secs so continuing with setup