Problem with custom script in user creation template

It gives me the following error:

+ FullyQualifiedErrorId : CommandNotFoundException Set-Mailbox : The term 'Set-Mailbox' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. At C:\Software\Personalizacion\ManageEngine\usernew.ps1:7 char:1 + Set-Mailbox -Identity $sAMAccountName -CustomAttribute15 $null + ~~~~~~~~~~~ + CategoryInfo : ObjectNotFound: (Set-Mailbox:String) [], Command NotFoundException + FullyQualifiedErrorId : CommandNotFoundException

my configuration:

powershell C:\Software\Personalizacion\ManageEngine\usernew.ps1 %sAMAccountName%

powershell:

Param(
[string]$sAMAccountName
)

Set-ADUser -Identity $sAMAccountName -mobile $null