Forgive my time zone, it’s morning now. Unfortunately I have deleted the problem project, it is a project to test how plugins work in package games when I saw 's page.
I do have an other plugin, “UMG Rich Text Box”. This plugin is out of date, so when I put it into the project’s Plugins folder and open the project, it showed recompile if my memory is correct.
After that is the problem, the 2 plugins works fine in the editor, but they won’t work in the packaged game.
But last night I tried the “copy paste” method(the last reply of RichText page), and a C++ iTween into a C++ project, now all the 2 plugins could work fine in a packaged game.