Did you happen to set a System Restore Point before doing that? Registry
cleaners seldom do anything but cause problems. My suggestion is to not use
them at all. Too often things get whacked that it things aren't needed
but--as you can see--are. One of the recurring themes in these (and other)
forums/groups are posts that start with "I ran a registry cleaner, and
then..."
If you didn't, then please post the contents of the error message. From
what I can tell that error usually is something like "The server name you
entered can not be found on the network." Verify that the server is in fact
the server it should be. If you have antivirus software that is integrated
with your email, try disabling the email integration and do your
send/receive again.
Joe