what mta are you using?
If sendmail, this has happened to me and it turned out to be the hoststat was getting a connection refused/timedout error and then having to wait 30 minutes before it would try again. In the meantime it was just immediately saying the connection was down and queuing mails. I found by killing all sendmail processes, restarting cyrus and sendmail and then purging the hoststat database will fix this issue, until it happens again.
We added the following line to our .mc file:
define(`confTO_HOSTSTATUS', `5m')dnl
This seems to work as expected so far ...
Cheers, Sebastian Hagedorn -- Sebastian Hagedorn M.A. - RZKR-R1 (Gebäude 52), Zimmer 18 Zentrum für angewandte Informatik - Universitätsweiter Service RRZK Universität zu Köln / Cologne University - Tel. +49-221-478-5587
pgp00000.pgp
Description: PGP signature
