This problem has been reported on OS X 10.7. It seems to be
related to a particular version of cURL which doesn't recognize
certain kinds of root-level certificates. The equivalent test on
other systems does not have the same failure. Strangely even the
certificate from the certificate provider suffers from the same
sort of problem.
In an effort to eliminate this problem, the SSL certificate for
api.postageapp.com will be replaced with one from a different