Forum Discussion
Assigning Microsoft 365 Phone System License fails with strange/confusing error message
Hello, for internal tests we currently assign the Microsoft Phone 365 License via the Admin Portal manually. All other Licenses are assigned automatically via synced AD Groups. If we now assi...
Late reply, but for those who stumbled upon this thread I just had this issue today, same error message. Issue turned out not to be with the email address listed in the error, but a separate duplicate email address associated with the stated account. So really there is a problem in error handling. To summarize the issue and fix...
*Error states "<EmailAddress>@contoso.com" is a duplicate on "<Person1>@contoso.com". The person was correct, the email address was incorrect.
*"<Person1>@contoso.com" had "<DuplicateEmailAddress>@contoso.com" listed as an alias
*"<Person2>@contoso.com" had "<DuplicateEmailAddress>@contoso.com" as a value for their mail attribute in AD.
Removing the "<DuplicateEmailAddress>@contoso.com" from "<Person2>@contoso.com" mail attribute in AD and performing a delta sync resolved the problem
