This article was previously published under Q328669
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This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.
You cannot send or receive e-mail, and Internet Mail Service cannot send or receive e-mail. If you telnet to port 25 on the Exchange Server computer, you may receive the following error message:
421 Exchange Server Name temporarily not accepting mail
This issue may occur if either of the following conditions is true:
The transfer mode of Internet Mail Service is not set to either Inbound Only or Inbound & Outbound.
There is not enough free disk space on the volume that contains the Imcdata folder.
To resolve this issue, configure the transfer mode of Internet Mail Service, and then verify that there is enough free disk space on the volume that contains the Imcdata folder. To do so, follow these steps:
In the Microsoft Exchange Server Administrator program double-click the Internet Mail Service connector, and then click the Connections tab.
Under Transfer Mode, click to select either Inbound Only or Inbound & Outbound.
Stop and then restart Internet Mail Service.
Verify that there is enough free disk space on the volume that contains the Imcdata folder.
NOTE: If you want, you can use the Exchange Server Optimizer program to move the Imcdata folder to a volume that has more free disk space.
For additional information about how to troubleshoot the Internet Mail Connector/Internet Mail Service, click the article number below to view the article in the Microsoft Knowledge Base:
191548 Troubleshooting Guide for the Internet Mail Connector/Internet Mail Service