Welcome to Community! It's important that you're able to upload your transactions effortlessly in QuickBooks Online. I'd be glad to assist!
If you haven't done so already, I suggest closing any apps that may be open in the background. In addition, I recommend resetting your app, or uninstall then reinstall it to ensure it's up to date. If you experience the same outcome, log into your QuickBooks Online account from a web browser.
If you require additional assistance please don't hesitate to contact us. A member of our Customer Care team will have the ability to review the issue in more depth, and escalate for further investigation if required.
Schedule a Callback or start a Chat: click (?) Help in the upper right in QuickBooks Online > enter "Contact support" > hit Contact Us > provide a brief summary of your situation > hit Let's Talk > choose Get a callback or Start a Chat.