title: Microsoft.Online.DirectoryServices.DirectoryValueExistsException on trying to add users to office 365 group (AzureAD)
body: <p>I tried to add a bulk of users into M365 group. However, the group contains 0 members. On checking the logs, I see that a lot of member adds were successful to the group and the ones that did log a failure were all for the following reason: Microsoft.Online.DirectoryServices.DirectoryValueExistsException. That was the sole reported reason for any failures to add members to that group. What could be the issue?</p>