At this point I am not able to generate any info when curl couldn't connect to host

I have tested using -v,  --stderr  and --output   options in curl

I have also tried to redirecting stderr to a file, for example :


    curl :::9999/version  2>  resu_ipv6_registration_fails.stderr

execution of this command in my console generates a resu_ipv6_registration_fails.stderr file with this info

    curl: (7) couldn't connect to host

but execution of this command into test sh generates an empty  resu_ipv6_registration_fails.stderr file