Thank you for your post.
It sounds like you performed all steps laid out in Knowledge Base Article #6496.
It is very possible that CURL is disabled, but FileMaker ships with CURL enabled.
Looking on a few forums, I found the following article:
Please let me know if this helps.
I am having an issue that might be similar to this.
Am on Filemaker Server Advanced 10 on Mac OS 10.5.8 (I have 12 but this set up has been held back because the developer is reworking the database for 12). The Filemaker database is on one machine and the webhost on another.
Am attempting to send email via SMTP from a script fired by either XSLT or PHP and am getting an SSL error. (At first I didn't know what the error was but I duplicated the script and when I just ran it inside a Filemaker client, the SSL error showed up. It was not readily apparent when fired by the web-fired scripts.)
On the webhost, I can actually set up the exact same email account I am using in the script dialog but in the Mail application. SMTP works fine from Mail and the SSL cert of the mail server isn't an issue.
I have also logged in as root on the webhost, added the cert in the System keychain to no avail.
Finally, I HAVE tested the interaction of the webhost SMPT with a Gmail account and it works fine.
The certificate for the email server I am using which requires an SSL authentication is provided by DigiCert and I believe it's an intermediate cert. I attempted to follow the instructions here (http://help.filemaker.com/app/answers/detail/a_id/6496) but mine is a webhost installed on an OS X client, not OS X Server and the instructions don't match my set up. I cannot find an httpd directory in /private/etc/ and the httpd.conf file I do find has no SSLCert entries in it. I also have no site directory in private/etc/apache2/
I need assistance in indicating to Apache that this email server's SSL cert is OK. Can someone help?