TXDataWebDataSet LoadAsync issue

Thank you for the details. Indeed, there was a problem with the way LoadAsync method was handling the connection errors. Fix will be included in next release.

If you want to fix it right now yourself, you should patch the following line in unit XData.Web.Dataset.pas (then one in source\core\web folder, pay attention as there is another one in source\core folder), here is the correct method:

function TXDataWebDataSet.LoadAsync: TJSPromise;
begin
  Result := TJSPromise.new(
    procedure(ASuccess, AFailed: TJSPromiseResolver)
    begin
      EnsureConnected(
        procedure
        begin
          FOpenResolver := ASuccess;
          try
            inherited Load([], nil);
          except
            on E: Exception do
            begin
              if Assigned(AFailed) then
                AFailed(E)
              else
                raise;
            end;
          end;
        end,
        procedure(Error: TXDataWebConnectionError)
        begin
          AFailed(EXDataWebConnectionException.Create(Error));
        end);
    end)
end;

The line you should update is this one:

        AFailed(EXDataWebConnectionException.Create(Error));