Problems with API Zoho

Hello, I am trying to get user portals, after generate the autotoken. I put in the browser as follows:

https://projectsapi.zoho.com/api/private/xml/dashbs/getportals?authtoken=c70302df229b3c75ddb9340a3df50cd8

And when I load blank page fits not returning the xml I ask.

And when I load the address, I get the page in blank the Zoho Project. No Returns the xml I'm asking.

¿Does anyone KNOW WHY THIS happens?

Also, I install an extension named Postman - REST Client and try calling the API via POST Method. A s you can see in the attachment I get 500 internal server error

Please I need help!!!!!!!!!!