Hello Juergen,
1/ Please provide the URL of the Track your order page.
2/ We suggest that you turn off the Mobile Content Optimization option (Theme Options > General) if you are using a cache plugin for mobile devices, as both optimization options can conflict with each other.
Also, please read this article – https://xstore.helpscoutdocs.com/article/100-how-to-speed-up-my-website
Best Regards,
8Theme’s Team