Hey Maksym_Khymii
Your 'MediaType' attribute value is incorrect. According to your screenshot, you've specified it as 'form-data' - but this isn't a valid value.
Replace 'form-data' with 'application/x-www-form-urlencoded'. The MediaType dropdown generates the 'Content-Type' HTTP header value in your request
Also - in your payload you have included HTTP headers (Content-Type, Content-Transfer-Encoding, 'Content-Disposition) - you shouldn't be specifying these in the payload.
Also - it looks like you're setting the boundaries yourself in the payload - if setup correct, these are dynamically generated. You should include JUST the payload and nothing else.
Hope this helps!
Cheers,
Rich