I have an application which resides on a Solarix box and a part of functionality involves sending emails to an SMTP server. I keep getting the message mentioned in the subject line when I try to send an email.
I dug up some sites trying to look for some cues as to why this is happening. What I found out was that the postfix queue which has all outbound emails for a linux (in my case Solaris) box, is either queued up or the folder is running out of disk space.
I am not sure how to resolve this error and if it's actually the queue which is blocked or I might be missing more information.
Anyone who has had a similar problem before? I am using the JavaMail API to send emails.
If that's really the case then it isn't a problem you can solve with Java code. In fact it isn't the mail client's problem at all. If the server is running out of resources then it's the server's problem and you should talk to the administrator of the server to see if he/she is aware of it.
I think I have narrowed down on the issue. I am using port 9999 on the SMTP server as advised by the SMTP server admin to send emails. This port might be blocked for sendmail outbound queue by the internal network firewalls.