This error comes up when using mail or an application in the Lotus Notes Client that is sending email. It is caused when you have a copy of a name in the personal address book as well as the normal names.nsf on the server.

One way to get around this error is to change your location settings.

Edit your location, to do this:

At the bottom right corner of your screen there is an envelope icon and to the left of that there is a word usually it is Office.

If you click on that, and select Edit Current you will see the location set up document.

Now click on the Mail tab.

On the field captioned "Recipient Name Lookup:", change this to "Stop after first match."

Save and Close.

Try again.