Is it just me or does it sometimes take forever to send a PM to someone…
here’s an example
(I took the pic like 10 min. ago)
I sent the PM last night at 11PM and it’s still in my outbox 
it sits in your outbox until the recipient signs in, unless they’re inbox is full, in which case it sits till there is space.
I’m neither a mod or admin, but this is how I understand it to work.
the mail will sit in ur outbox till the recipient opens/reads it
ah I see… I thought the PM had to go out of my outbox first before the recipient would get a chance to read it…
Thanks for the clarification 
http://www.phpbb.com/support/guide/#section4_3_1
4.3.3: The Outbox
When you send a PM, the message goes to your Outbox. It remains in the Outbox until the recipient visits his/her Inbox, at which point it is moved from your Outbox to their Inbox. While the message remains in your Outbox you may edit or delete your post if you like. The message remains in your control until it is received.
I remember when saying RTFM was a big thing :dunno:
Once it is in your sentbox you know its been received by the user.
Consider your PM a registered letter, where the Outbox is the post office,
and the Sentbox is the delivery confirmation once they’ve “signed” for the
mail.