It's best to start by checking your users' access, Jones. Allow me to elaborate further.
Since you mentioned that you usually have two people creating invoices in your QuickBooks Mobile app, it's essential to verify if the access permissions for your users have not accidentally changed. This could be the reason why you can no longer create invoices simultaneously with the other user.
However, if your user has the necessary access as mentioned above, we can then proceed with basic troubleshooting steps to resolve any app-related issues that are generating the error message you're user have received.
Follow the steps below:
For IOS devices:
- Go to Settings, then tap General.
- Tap iPhone Storage, then tap the QuickBooks Online app.
- Tap Offload App.
For Android device:
- Go to Menu, then tap More Options.
- Tap Settings, then Refresh Data.
- Tap YES to confirm.
If the issue persists, you can then uninstall and reinstall the application to make sure that your application is up-to-date.
Additionally, I'm adding this resource to assist you with receiving payments in your QuickBooks Mobile App: Receive an invoice payment using the mobile app.
Our team is committed to providing thorough support as you explore these solutions. If you require more information or assistance with creating invoices in your QuickBooks app, please contact us through this channel. Your collaboration is appreciated, and we are eager to help you optimize QuickBooks for your needs.