Sort by Timestamp not work

[david_graylog13 (david)]

Hi agian
I’m using a pipeline get Timestamp from message body and save to new filed(New_Time)
my pipeline:

rule "CreateNewFormatTimestamp"
when
 from_input("5e8c0edb50401d5943c76fcf")
 then
//"Timestamp":"2020-04-14T17:26:47.6146998+04:30"
let GetTime = ($message.Timestamp);
//2020-04-14T16:39:01.214
let GetTime = substring(to_string(GetTime), 0, 23);
set_field("New_Time", parse_date(value:to_string(GetTime), pattern:"yyyy-MM-dd'T'HH:mm:ss.SSS"));
end   

Then checked Elasticsearch type field.

type is date but sort does not works yet!

Also, this field (New_Time) is not shown in the list of fields left side SORTING.

Thank you for your patience.