try with debug-mode on:

LWP::ConsoleLogger::Easy::debug_ua($myUA, 6);
$IO::Socket::SSL::DEBUG = 3; # SSL debuggging mode
[download]

Long shot: also, ssl_opts supports SSL_version, e.g. SSL_version => 'TLSv1' Maybe some incompatibility of versions that you/them can't handle?

But before that make sure your useragent string is set to something sensible and not 'www-perl'... And also set your LWP timeout to something long (seconds), $myUA->timeout(100);, oh and that you upgrade your modules if you can.

I have also been troubled with 500 Server closed connection without sending any data back. I have come to an unfounded conclusion: maybe it has nothing to do with SSL because I can see the handshakes, the sockets opening etc. So, just maybe that's their way to tell me to bugger off.

Btw, if in your headers you see 'Internal response', that's LWP issuing that and not the server. (I mean the wording of the error does not come from the Server - obviously if it's a timeout).

bw, bliako