I am not really a Linux admin (mostly focused on Windows) but we do have one WebServer that runs Red Hat 6. This server has a web app that runs on ColdFusion 10 (Update 14). I generally just login to it to update. Well, last week after the Shellshock announcement I decided to update with the latest patches, the problem is that afterwards the server stopped sending emails to clients (usually receipts of transactions). I changed to different mail servers, including our local Exchange and even Amazon SES and it won't send emails. I verified with the programming team that manages the app and there are no problems within the application, in fact ColdFusion is "sending" the emails. If I reboot the server then all the emails that were "sent" are suddenly, well, sent, and it keeps sending emails for an hour or two until it suddenly stops once again. So that means its spooling all those emails somewhere but not sending them for some reason. If I open the terminal and type the "mail email@email.com" command the messages are sent without issue.
How can I verify where the problem is coming from? How to fix it? I am close to restoring the server from a tape backup from two weeks but I'd vastly prefer to fix it.
UPDATE: Coldfusion. After further verification... It says emails are being sent. In fact the spool folder in CF is empty, same as Undelivered. At least ColdFusion thinks its sending the emails without issue. Mail.log doesn't inform me of any issues.