TLS_CA_File should have a default value in the code or its definition in ssmtp.conf be uncommented by default. It doesn't hurt to have it when not using TLS, and it is now seemingly required if TLS is in use. Previously my ssmtp was using TLS and working but when it got upgraded to a version that added the verification functionality, it no longer succeeded in sending anything because TLS_CA_File is now required for TLS to work, and it didn't have a valid default value after package upgrade.
ssmtp-2.64-11.fc19 has been submitted as an update for Fedora 19. https://admin.fedoraproject.org/updates/ssmtp-2.64-11.fc19
ssmtp-2.64-11.fc20 has been submitted as an update for Fedora 20. https://admin.fedoraproject.org/updates/ssmtp-2.64-11.fc20
BTW uncommenting the value is only a slight improvement because it won't take effect if the new config file gets installed as *.rpmnew which is quite likely. Better would be to have a default in code.
I'll examine the code and try to see how well it works to also add a default value for TLS_CA_file via the TLS patch.
Package ssmtp-2.64-11.fc19: * should fix your issue, * was pushed to the Fedora 19 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing ssmtp-2.64-11.fc19' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2014-1162/ssmtp-2.64-11.fc19 then log in and leave karma (feedback).
ssmtp-2.64-11.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.
ssmtp-2.64-11.fc19 has been pushed to the Fedora 19 stable repository. If problems still persist, please make note of it in this bug report.