KC868-A16 esp32 board (A16)as upgrade of a Homevision Controller?

[hjahend]

Tried to install my spare a16 board from you. All went well, except this error message in the logging:
INFO ESPHome 2024.8.3
INFO Reading configuration /config/esphome/kc-a16.yaml...
WARNING 'kc_a16': Using the '_' (underscore) character in the hostname is discouraged as it can cause problems with some DHCP and local name services. For more information, see https://esphome.io/guides/faq.html#why-s...evice-name
INFO Starting log output from 192.168.1.50 using esphome API
WARNING Can't connect to ESPHome API for kc_a16 @ 192.168.1.50: Error connecting to [AddrInfo(family=<AddressFamily.AF_INET: 2>, type=<SocketKind.SOCK_STREAM: 1>, proto=6, sockaddr=IPv4Sockaddr(address='192.168.1.50', port=6053))]: [Errno 113] Connect call failed ('192.168.1.50', 6053) (SocketAPIError)
INFO Trying to connect to kc_a16 @ 192.168.1.50 in the background

How to remedy this?