Problems with api getUsers

Hello,

I want use getusers api with url

Https://crm.zoho.com/crm/private/xml/Users/getUsers?authtoken=xxxxxx&scope=crmapi&type=AllUsers
And i have for result

<Response> <url = "/ crm / private / xml / Users / getUsers"> <error> <code> 4600 </ code> <message> Unable to process your request. </ Message> </ error> </ answer>

I do not understand.

Thank you for your response