Press Ctrl+V to paste. Your browser doesn‘t support pasting with the toolbar button or context menu option.

@Pracheth the issue is about to use the GUI button "Paste from word"

For anyone that is facing this you can try something like:

CKEDITOR.on("instanceReady", function(event) {
  event.editor.on("beforeCommandExec", function(event) {
    // Show the paste dialog for the paste buttons and right-click paste
    if (event.data.name === "paste") {
      event.editor._.forcePasteDialog = true;
    }
    // Don't show the paste dialog for Ctrl+Shift+V
    if (event.data.name === "pastetext" && event.data.commandData.from === "keystrokeHandler") {
      event.cancel();
    }
  })
});

which will force the old dialog, looks like is something asked since 2017: https://github.com/ckeditor/ckeditor4/issues/469#issuecomment-524185244

That solution works, but it doesn't do direct pasting of clipboard content, but it's opening paste popup instead.