Unable to set x-www-form-urlencode params in http body-Getting error "unsupported_grant_type"

Im unable to user x-www-form-urlencode in http body. As soon as I add paramters to x-www-form-urlencode in HTTP Body and save is not saving the params instead it goes to text format automatically. Is there anyway to add httpbody x-www-form-urlencode params through script.

Same issue for me also. I add paramters to x-www-form-urlencode in HTTP Body and save is not saving the params…can any one help us please