what does it mean when a email has been in que too long?

Answer 1

A queue is set up for an email message so that if it cannot be delivered immediately to a particular domain, it may be delayed. Also, based on server traffic, an email message may be in a queue (an electronic line so to speak). If you get a message saying that an email message has been in queue too long, it means that there's probably something on the recipient's side that is preventing the email from being delivered. The mailbox may not be available for example.

Answer 2

its like a holding pattern for a plane..either it has to land or move to another airport........so the que is sent or dies.