This looks like one of those problems where it is easy to fall down a rabbit hole.

I don't have experience with this problem, so be careful I don't send you down one of those rabbit holes.

$sender = new Mail::Sender({from => 'janedoe@madeup.org',smtp
     => '10.11.74.18'})
[download]

For exploration purposes, reading IO::Socket::SSL docs it looks like you might be able to disable the client side from verifying the certificate. If that hides the problem then that suggests the problem is in the certificate verification.

SSL_verify_mode => SSL_VERIFY_NONE
[download]

From the server log line 22, it looks like the certificate is for "webmail.somedomain.org", while your script is connecting via IP address. Does it make a difference if you specify "webmail.somedomain.org" instead of the IP address?

A quick google for godaddy CA openSSL returns some results that may be apropos, or perhaps just a very deep rabbit whole.