I also had problem with customizer, because td_boost conflicts with this plugin. But its only for preview. The settings work fine, and I can manually test the amp urls.
However, I noticed the AMP tag is not inserted automatically by this plugin to each page. So even if someone clicks the url from Google search, it opens the desktop url on mobiles too.
ok, my bad… the tag does get inserted … perhaps I have to wait for Google to re-index the new url format!
@oweibor It seems to be a problem from any of your current plugins. Please check them by deactivating them one by one.
@csine Thanks for help and update.