We had a problem when our provisioning system would not update the “managed by” property for a distribution list. Further investigation showed that the distribution list’s e-mail address had a strike through like this: (Seen in the DL’s properties using EMC) email@company.com We could not add a new smtp address to the group nor delete the current address. We then opened ADSIedit to have a more in depth look. We then noticed that the SMTP address in proxyAddresses had a space before the @ in the SMTP address. We rectified that and the strikethrough disapeared. We made the changes and managed to provision the DL without any problems.