the last couple of days pending submission queue has been growing and no mail internal or external is being delivered. message tracking shows each message being submitted to the pending submission queue, where they just accumulate.
this seems to have followed the system disk running low on space (140mb). iis logs were cleared and space now ok, then these problems occurred about a day later.
obvious stuff checked:
services all ok , restarting smtp virtual seems to resolve problem for a minute or 2 before q starts growing again, same with a reboot, although we did get it working for an afternoon yesterday and thought we had resolved it.
we have noticed the inetinfo process using v few cycles when delivery worked ok, but a constant 25% when q is growing.
logging has been set to max for messagetransport, but doesnt seem to show much except for 7010 errors relating to specific ip/clients.