We have an Exchange Server 2010 V 14.01.438 running on Window Server 2008 R2 Enterprise, which stopped receiving incoming emails about three hours ago, however everything we checked appears to be in order.
Items we checked so far:
- Internal emails are working fine
- Outgoing emails are working, a 10-14 second delay more than usual is felt
- Nothing in incoming queues on management console
- New incoming messages do not appear be go through the ORF (so we thought perhaps an incoming port block)
- SMTP test from MXToolBox passed
- Server is not blacklisted (MXToolBox)
- Telnet to server's port 25 works fine, also from outside the network
- Senders (we used gmail for testing) are not receiving any error messages
- We tried restarting the information store service and the server itself
- Additional info: No update / work was done on the server in the past week. The drive which is running Exchange has 8.5GB free. Server does not appear to be under any loads
Any suggestions ?
Best Answer
Exchange server enters back pressure mode and refuses external mail when available disk space drops to around 2%.
If there is no obvious reason for your server to be running out of space, check that your backups are running properly as otherwise your exchange transaction logs will eventually fill your disk.