I can’t add an entry to the allow list on Exchange Server

I wanted to add a new anti‑spam entry to the allow list on Exchange Server 2007, but I got an error.

The IP List entry operation has failed with an exception. 
The error message is: "Access is denied" It was runnig command 
'get-IpAllowListEntry -Server 'SERVER"

The IP List entry operation failed with an exception. The error message is: “Access is denied.” I was running the command Get-IPAllowListEntry -Server ‘SERVER’.The error was caused by insufficient permissions. The reason is described in “How to Delegate Server Administration” at http://technet.microsoft.com/en-us/library/bb331957(EXCHG.80).aspx. You need to assign the ServerAdmin role to your account:

Add-ExchangeAdministrator -Identity "contoso.com/Users/KwekuA" -Role ServerAdmin -Scope server1.contoso.com