The suggestion of looking at the curl connection is a good one. You can compare what you have with curl --trace tracefile to what you see with use LWP::Debug qw(+conns);

You can use libcurl from Perl. It shouldn't be necessary to resolve such a simple problem, though.

Curl takes the user:pass@ out of the url and just puts the user and password in the credentials, so it should work the same.

Are you sure the user name contains an '@' character? The user name is just the part before the ':'. You would have to URL-encode an '@' sign for curl (not for LWP).