OK I think my problem is that the Perl library cannot find the authentication certificate. I have tried to specify the certificate, but still it doesn't work.
Since my Perl script will be used in the preparation/configuration phase, I don't really care about the communication security, and I bypass the host verification as a workaround.
So what I need is just one line:
$user_agent = LWP::UserAgent->new( ); $user_agent->ssl_opts(verify_hostname => 0); # BYPASS HOSTNAME VERIFICATION! $url = 'https://msa1040_ip_address/api/login/' . $md5_hash; $request = HTTP::Request->new( GET => $url ); $response = $user_agent->request($request);
... and BOOM! It works.