Important notes regarding the Any User/Catch All account

The Any User account is no longer supported in the new exchange platform.
The new mail system does not support AnyUser accounts as it is widely considered to be bad practise because existence of these accounts create the ability to cause UCE (Unsolicited commercial email/SPAM).

As a work around solution please create a new e-mail account (named i.e. AnyUser@yourdomain.com) in MyAccount and add aliases to this account for every address you want to accept mail to.

To create alias accounts: 
1. Click exchange admin in the MyAccount
2. Click the Edit-icon to the left of the red x button on the right hand side

3. In the Alias box down on the left hand side enter the first name (prefix) of the email address. Separate the aliases by a new line. I.e: