Issue sending emails as a result of subject line being too long

[eluser]Dandy_andy[/eluser]
I thought I'd share this as I've seen from various other forums that people have had the same issue. I have been using Codeigniters Email Class since i started using Codeigniter and on a recent project, some of the emails were going through OK and others weren't. I spent days trying to figure out why. For some emails being sent, I was seeing the following error:-

Code:

451 See http://pobox.com/~djb/docs/smtplf.html.
The following SMTP error was encountered: 451 See http://pobox.com/~djb/docs/smtplf.html.
Unable to send email using PHP SMTP. Your server might not be configured to send mail using this method.

Everything online was pointing to the set_newline parameter but I couldn't make sense as to why some emails were going through and others weren't. I tried tweaking everything...

It turns out in the end the issue was with the subject line. As simple as that. If the subject line is too long, the email isn't delivered. Perhaps someone can clarify what the maximum length of the subject line needs to be? Since I have shortened all my subject lines, all emails are going through nicely now. It was nothing to do with my SMTP server or newline settings.

[eluser]CroNiX[/eluser]
http://stackoverflow.com/questions/15922...ngth-limit