Hey @Suave1 !
I'm sorry to hear about the trouble you're experiencing with our Invoicing App! As a start, we can go through some initial troubleshooting to see if we can help you resolve the problem.
If following these steps don't resolve the error you're experiencing, please let me know. To help us better understand the issues you are experiencing, please provide the following information: the version of the app you are using, the type of device you are using, some screenshots of the error you're seeing, and the operating system version. I'd be more than happy to look into this further for you, or report this to the development team for review if necessary.