##proxy authentication
$PROXY_USER = uri_escape($PROXY_USER);
$PROXY_PASSWD = uri_escape($PROXY_PASSWD);
$PROXY_IP = uri_escape($PROXY_IP);
	
           
my $proxy_url = "${PROXY_USER}:${PROXY_PASSWD}"."\@${PROXY_IP}:${PROXY_PORT}";	### oh, just realized, looks like forgot to add "http://". here before proxy user that's why it failed, can you just confirm the same.

$ua->proxy(https => "$proxy_url");