new user suddenly can't access her QBO account

I appreciate you for reporting this to us immediately,@quickbooks12. 

We'll take some troubleshooting steps to improve the program's performance and fix the problem with the denied access of your user.

Your user can start by clearing your browser's cache to refresh your browser. Sometimes, old or corrupted files in your cache or cookies can cause web pages to load incorrectly, which might be why your access is being denied.

Alternatively, we can try using a different supported browser to see if the issue is specific to the browser you are currently using.

If the issue persists, your user can try these steps to recover their account:

1. Go to our sign-in help page and enter your account's phone number or email address.
2. Choose Password, then select Forgot password or Text a code to [your number].
3. Look for a message containing your code in your text messages or email. Note: Open your email inbox in a new browser tab, but make sure to keep the original tab with the sign-in page open.
4. Follow the instructions provided to log in. You'll have the option to reset your password if prompted, or you can choose to skip this step.

After doing all the possible solutions for users with access being denied, you can reach out to the Support Team to your QBO account by clicking on this link: Get help with QuickBooks products and services.

For more information on how to resolve access denial issues, please refer to this article: Resolve sign-in issues in QuickBooks.

Also, if you need to change your sign-in information for your Intuit Account, this article may be helpful: Update your account credentials.

You can always revisit this thread if you have further inquiries about your user's QuickBooks access or any other QuickBooks-related concerns. My team and I are always here to support you.