Outlook 2010 unable to expand distribution list. Operation Failed

Issue: Outlook 2010 unable to expand distribution list.

Error message:  cannot perform the requested operation. the command selected is not valid for this recipient. The operation failed

Resolution: The distribution had a forward slash(/) in the name. So renaming the DL and removing the forward slash resolved issue

Note: After your rename the DL, update the legacyDN accordingly