Hi there,
Thanks for connecting with us here. QuickBooks is designed to be an easy-to-use program. It's vital you're able to use the app without running into issues. Rest assured, I'll be happy to help so you're on the right track.
Based on what you've described, I highly recommend uninstalling and reinstalling the app. This is a great way to troubleshoot issues that may be affecting the app. By reinstalling the app, this ensures you're on the latest version of the mobile app. I encourage you to try this out and let me know what happens.
You're more than welcome to keep me posted in the comments below. I've got your back.