Hello! Welcome to our forum!
Please stick to English only.
Because you are not even writing the error in English, I think it’s a good guess that you are also running auto-translation in your browser. This is not compatible with the current version of the app - see this topic: INOP after importing from SimBrief - #21
In the next version of the app, this will no longer be a problem! Until then, disabling the auto-translation will fix the issue for you.
Kind Regards,
Malte