We still observe "In Progress", nothing gets accepted in the last 2 days. It started to happen on March 11th evening CET

Thanks for the hint; how can I retrieve local ip address using nw_connection_t? I tried to use nw_endpoint_create_host, nw_parameters_set_local_endpoint, but nw_endpoint_get_address always returns null.

Correct; we did not notice this 'getaddrinfo' hanging for 5 seconds yet on macOS Sonoma on systems where the Sonoma was preinstalled. But it happens on some systems which were upgraded from a older macOS version, like Ventura Right, we develop customer application and deploy worldwide to customers which are then used in their networks.