Hi @william.a.maguire

There are two errors in the request body:

1. "ValidationOptions" and "UseUserPreferencesForValidationOptions" cannot not be used in the same time. Remove the later one should work.
2. If "QueryStartDate" and QueryStopDate" are set, the ReportDateRangeTypeshould be "Range", not "Delta". If you must use "delta" as the range type then don't use QueryStartDate and QueryStoDate, use "DatesAgo" parameter instead.

Here is THE MODIFIED request body I tested and worked. Please note I used onDemand extraction instead of report template extraction as in your original request :

{ 
"ExtractionRequest": {
	"@odata.type": "#ThomsonReuters.Dss.Api.Extractions.ExtractionRequests.TickHistoryTimeAndSalesExtractionRequest",
	"ContentFieldNames": [
		"Correction - Ask Price",
		"Correction - Bid Price" ],
	"IdentifierList":{
		"@odata.type":"#ThomsonReuters.Dss.Api.Extractions.ExtractionRequests.InstrumentIdentifierList",
	"InstrumentIdentifiers":[{
		"Identifier":"PSN.L","IdentifierType":"Ric"
	}],
	"ValidationOptions":{
		"AllowOpenAccessInstruments":true,
		"AllowHistoricalInstruments":true}
	},
	"Condition":{
		"MessageTimeStampIn":"GmtUtc",
		"ApplyCorrectionsAndCancellations":true,
		"ReportDateRangeType":"Range",
		"QueryStartDate":"2018-01-29T00:00:00.000Z",
		"QueryEndDate":"2018-01-29T00:01:00.000Z",
		"Preview":"Content",
		"ExtractBy":"Entity",
		"DisplaySourceRIC":true
	}
    }
}