After applying a patch to fix a cfmail problem in 8.01 I noticed a new problem. When creating more than 3000 or so emails in one go about 100 ended up in the Undelivr directory. There was nothing wrong with those emails, dropping them into the spool directory by hand sent them quickly on their way.
The exception.log was showing “IOException while sending message”. I reported this to an Adobe engineer in July 2008. In October the engineer found that the issue can be “fixed” by increasing the max session size in the Microsoft SMTP service. Microsoft don’t recommend increasing it too much but the more I increased it the less emails were sent to the Undelivr directory.
The bug is with ColdFusion and it appears to not behave correctly if the SMTP server closes a session because it has reached the maximum size. ColdFusion should react by simply opening up a new session and continue to send emails from where it last left off. But it doesn’t do that. This bug has been affecting a major application for nearly a year and Adobe haven’t been able to fix it.
MS SMTP logs “552 4.3.1 Session size exceeds fixed maximum session size” which is fine, it expects the app at the other end (CF) to continue by opening a new session. I’ve now increased the session limit to a very large amount but as the application is used more the limit is reached and emails stop being sent again. CF is misbehaving and is causing operational headaches.
Has anyone else had similar problems? I’m looking for others who can help add some pressure to get this bug fixed. Please do get in touch. Needless to say I’m very disappointed that CF is unable to send a large amount of (legitimate, non-marketing) emails problems.