Can't find textframe using doc.textFrames.itemByName("myTextFrame");

In a document i have inserted a textframe and added myTextFrame into its Script Label.

When trying to get it by js using doc.textFrames.itemByName("myTextFrame"); is says the object is invalid.

When trying doc.textFrames[0] i get a textframe with label myTextFrame.

Having same issues with rectangels -> var rect = doc.rectangles.itemByName(rectName);