GET calls using /sdpapi/request/ does not work

GET calls using /sdpapi/request/ does not work

Can anyone help me check what causing the error?

The parameter is:
{
"operation": {
"details": {
"from": "0",
"limit": "50",
"filterby": "All_Requests",
"account": "My Org Inc"
}
}
}

The return is:
{
"operation": {
"result": {
"message": "Mandatory input elements from, limit and filterby not found",
"status": "Failed"
}
}
}

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