The Security Certificate on the NUIM Email Server was updated on 27 January 2009.
When this certificate is updated, your email client may alert you to the change and prompt you for a response. Eudora Version 7 will have downloaded the previous security certificate, which it relies on to establish a connection to the email server. The first time it contacts the email server after the upgrade of the security cert, you will be prompted as follows:

To continue using Eudora and access your emails, please click Yes. Eudora will accept the new certificate for this and all subsequent communications with the email server.