Thank youv @bigevilbeard With your help I got the information I needed, but I am confused, isn't the API "dataservice/statistics/interface"? Where did this "/dataservice/data/device/statistics/interfacestatistics" come from? 

Hello,I get this error message when I send a GET to the API /dataservice/statistics/interfaceError:{    "errorMessage": "must not be null"} I'm using POSTMAN with the SD-WAN sandbox, and I'm able to make every other request with success, but not this...

You're an angel