I actually have had the same problem as well. This seems to have been
discussed quite a few times in this group but there doesn't really
seem to be any solutions offered. I have an app in beta and so far one
of my users have reported having to wait over 15 minutes and still not
seeing anything (app sends a C2DM for the phone to report its status
to the app server). They did say however after refreshing the page (on
my application server to get phone status) they were able to see the
results right away. I saw no errors in the logs that log the response
from C2DM. I currently suggest to my users to refresh the page (so it
sends out another request to C2DM) or if that doesn't work to manually
unregister, force stop the app via manage applications and then re-
register.
So just wondering if anyone here has some Pro tips on how to cut down
the wait time? I typically never see these types of delays with other
Google products (like GMail, Calendar) who Google claims also uses
C2DM.