Hi, Curra. Ensure all fields, such as descriptions, rates, quantities, and custom fields, are filled correctly without invalid characters, empty fields, or unsupported formatting before saving or emailing the invoice.

If the problem persists, reset the app to clear stored data, as this works similarly to clearing your cache. Below are the straightforward steps.

For Android devices: 

1. Select the menu at the top right and choose Settings. 
2. Press Refresh Data and choose Yes.

In your Phone Settings: 

1. From your settings, tap Apps (varies by device).
2. Choose the QuickBooks app from the list and select Storage.
3. Select clear data.

Once done, restart your device and reopen your QBO mobile app to double-check.

However, if the same issue occurs, let's uninstall and reinstall the app. For detailed steps on how to do this, please refer to this article: How to download the QuickBooks Online mobile app.

If you have any questions or clarification, please let us know.

OK, tried the suggestions including deleting and re-installing the app twice.....

Had reason to modify an existing invoice today and am getting the same thing, have attached a screenshot again

l really need to get this fixed

on a Pixel 9 phone, android vers. 16 

This has not been an easy experience, @curra. I acknowledge your effort in doing the troubleshooting steps to resolve the error so you can modify your invoice today. 

Since the issue persists, I recommend contacting the QuickBooks Online (QBO) Phone support team to further isolate this error based on the screenshot you shared. You will have a one-on-one interaction to determine when the error started and will ask for some relevant information. Once the root cause is determined, they can help and guide you on what to do to fix the error. 

Here's how:

1. In your QBO mobile application, go to the Menu icon.
2. Select the All tab and choose the Help option below.
   
3. Tap Ask QB assistant a question.
   
4. Click on Contact Us below.
   
5. In the What can we help you with? section, pick Ask about something else.
   
6. Type in a short description of the error and Continue.
   
7. Choose either Chat or Callback.

In the meantime, you can log in to your QBO account via a web browser and edit your invoice transaction there so you can finish your task today.

I appreciate your gesture in giving me the chance to assist you today with your issue in editing an invoice using the QBO mobile app. Whenever you're free or have more questions, leave a comment below.