Scroll API nest for large datasets

Hello guys, I am using scan and scroll api for ES nest 5.5 to retrieve documents over 1.3 million in size(6 fields/document)
my scroll api works fine if I retrieve less number of documents(around 800000) but when I want to retrieve large documents(1.3 million) it just fails. I dont know what is going wrong. I am trying to do this on C# visual studio and also make a web api and host as a microservice on service fabric app. both places it is failing. on visual studio, I get error: unexpected ES exception, sometimes I get web request aborted and sometimes " search context lost" even though I am giving new scrollid in each loop. below is my code. please help me. its urgent.

ISearchResponse initialResponse = this.ElasticClient.Search
(scr => scr.Index(indexName)
List results = new List();
if (!initialResponse.IsValid || string.IsNullOrEmpty(initialResponse.ScrollId))
throw new Exception(initialResponse.ServerError.Error.Reason);
if (initialResponse.Documents.Any())
string scrollid = initialResponse.ScrollId;
bool isScrollSetHasData = true;
while (isScrollSetHasData)
ISearchResponse loopingResponse = this.ElasticClient.Scroll(scrollTimeout, scrollid);
if (loopingResponse.IsValid)
scrollid = loopingResponse.ScrollId;
isScrollSetHasData = loopingResponse.Documents.Any();
this.ElasticClient.ClearScroll(new ClearScrollRequest(scrollid));

Please help

I'm closing this as it's a duplicate of Scroll API(C# NEST) fails