INVALID HEADER in mail TO YOU explained

I'm administrating a web, ftp and mail server for my company, using ISPconfig 3 (on a ubuntu 9.10 box). i didn't change much of the settings related to emails.

Sometimes i get a INVALID HEADER in mail TO YOU from .... email. I know it can be a spam but in this case i saw that i wanted that email. It's a activation link for a site. Is there any way to access that mail (as the mailbox owner or the server admin)?

 

Can you see from the mail log what happened with that mail?

 

This time the email was sent to the recipient, so it's ok.
But if the email is quarantined or not sent to the recipient, can i somehow see it or get it past the quarantine to the recipient?

 

I can't tell - it depends on what the mail log says.

 

just to clarify

i'm sorry for not being specific.
I've solved this email because the message stated 'The mail has been sent to the recipient'.

I will google around in the spamasassin and mail websites to find more info about how spam is quarantined and if it is deleted or recoverable.