API FrappeClint in php problem

i use GitHub - tmimori/How-to-connect-to-ERPNext-v5-API-with-PHP5: How to connect to ERPNext v5 API with PHP 5 in my project, and i login success.
But i can’t use insert function
it shows

how to fix this problem. thanks!


Can you share the request data?

It looks like you are passing invalid json to insert function.