Mobile deposit keeps giving me the “ whoop “ error message but nothing is wrong with my check.

I understand your concern about the issue you're encountering. 

Currently, there is an ongoing investigation (INV-91721) concerning mobile deposits in QuickBooks Online (QBO). Rest assured that our Product Engineers are dedicated to resolving this issue promptly and implementing a permanent solution.

While we work on resolving the problem, I suggest contacting our support team. They can include you in the list of affected users and ensure that you receive timely email updates as new information about the investigation becomes accessible.

Let me walk you through the steps on how:
 

1. Sign in to your QuickBooks Online company.
2. Click on Help (?).
3. In the Assistant tab, type in Talk to a human.

For detailed information about our support's availability hours, kindly visit: QuickBooks Online Support.

Additionally, it would be beneficial for you to explore this article that provides guidance on examining bank and credit card transactions that have been downloaded in QuickBooks: Categorize online bank transactions in QuickBooks Online.
 

If you need any further assistance or have more questions related to QuickBooks, notify me by leaving a comment below. I'll be available to provide the assistance you require.