Odd. Nothing SSL relevant has changed for quite a while and all installs and tests on Ubuntu work fine AFAIK. A firewall could make this happen, but then one would expect it to always fail. Some of the tests access public networking and may thus suffer from a poor network connection. These are by default disabled unless the environment variable SWIPL_PUBLIC_NETWORK_TESTS is set to true.
The way to get more detail is a little complicated for ssl. Starting from the build directory, run:
cd packages/ssl
../../src/swipl ../../../packages/ssl/test_ssl.pl
<banner>
?- test_ssl.
% PL-Unit: ssl_options ....... done
% PL-Unit: ssl_server . done
% PL-Unit: ssl_keys ..... done
% PL-Unit: https_open . done
% PL-Unit: ssl_certificates ................................ done
% PL-Unit: crypto_data_encrypt . done
% All 47 tests passed
true.