diff --git a/SynHttpSrv.pas b/SynHttpSrv.pas
index fc5e7f9..335b505 100644
--- a/SynHttpSrv.pas
+++ b/SynHttpSrv.pas
@@ -1993,7 +1993,7 @@ function THttpRequest.GetStrProp(Index: integer): string;
 
 procedure THttpRequest.SetStrProp(Index: integer; const Value: string);
 var
- i: integer;
+ i: int64;
 begin
  if (Index >= 0) and (Index <= High(StrPropNames)) then
   case Index of
@@ -2011,7 +2011,7 @@ procedure THttpRequest.SetStrProp(Index: integer; const Value: string);
    18:
    begin
     i := 0;
-    if TryStrToInt(Value, i) and (i > 0) then
+    if TryStrToInt64(Value, i) and (i > 0) then
      Headers[StrPropNames[Index]] := Value;
    end
    else