Failt to take responses from API

Hi everyone how to get the responseId from qualtrics, I follow up this
But when I run the first link
1.-https://api.qualtrics.com/api-reference/reference/legacyResponseImportsExports.json/paths/~1responseexports/post
{
"meta": {
"httpStatus": "400 - Bad Request",
"error": {
"errorMessage": "Invalid parameter. Must be a valid ISO 8601 date. param=startDate, value='\\"string\\"'",
"errorCode": "ADTP_6"
},
"requestId": "7f78f4da-7c84-474c-9dd5-f89148db2818"
}
}
Any idea?
Someone know how to obtain the responseID fron a survey using the API

Thanks!