Symptom:
When a new user is created, in some cases an SMTP address is generated in the format of username2@domain.com instead of username@domain.com although there is no such existing address on the network
Cause:
Issue is possibly due to the x400 configuration on the e-mail address policy:
When the email address is stamped, x400 finds the 2nd user as duplicated as the user’s First Name and Last Name are same.
So it adds 2 in the X400.
As the X400 found it as duplicate and added 2 , SMTP also follows the same and adds 2 to address.
Solution/Accepted workaround:
Remove x400 configuration from e-mail address policy and restarted the Exchange services.
*Please note that X.400 address function is not necessarily required in pure Exchange 2007/2010 environments.
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