What's happening is that the server you're sending to isn't closing the connection properly. We're unable to read the final "ack" from them, after we send the final "dot".
alas, this isn't something wrong with iMS that we can fix, but is more likely to be a network or other problem outside iMS.
It means that the server on the other side isn't responding the way we expect it to.
When you connect to any smtp server, you expect to get a banner. When you begin the conversation with HELO or EHLO, you expect to get a status response back. We're not getting that, so we have to tell you that there is a problem. It's on the other side. . .