Error with my API made Django REST framework

Hello:

This tool is very impresive, i am using for automate my api test, everything is great both when i want to use the Verify Element Property Value, it show error this

Unable to verify element property value (Root cause: groovy.json.JsonException: Unable to determine the current character, it is not a string, number, array, or object

The current character read is ‘<’ with an int value of 60

Unable to determine the current character, it is not a string, number, array, or object

line number 3

index number 2

^)

I use django REST, it kind show of html not JSON raw, you can help me for this??