The same thing has been happening to me for about one week. I cannot receive any offers nor IMs into sl if I am logged out at the time, even though the sender gets the standard blurb that their IM or shared item (including marketstreet purchases) will be stored and delivered later... they have NEVER delivered to me for the past week - not even into my trash. ONLY way I can receive ANYTHING is if I am logged in at the time.
I was on sl Premium Support Chat about it last night for about an hour, and the tech could find nothing on it, so must be a fairly new bug. I have uninstalled every viewer and deleted every folder containing anything remotely referencing sl on my pc.
Did a clean re-install of latest Viewer3 from Linden. Logged into Hatton and set my Av to one of the standard Vehicles, and then the standard Unicorn, just to be sure I got rid of anything I might be wearing if corrupted. Cleared all caches and reset the Debug to Default, and logged out.
Went to another pc and logged in as alts - sent my premium some inventory and IMs as tests.
Returned to primary pc and logged in as my primary av, and still - received NOTHING while logged out - even though my alts got the blurb that all is well and the things would be delivered.
Hope somebody can fix this.