I truly appreciate your diligence in performing troubleshooting steps, dorretti. 

Since you're still unable to transfer the primary admin role to your client despite receiving a success message, I recommend contacting our Quickbooks Online Accountant (QBOA) Support Team. They possess the necessary tools to securely access your account, conduct an investigation, and assist you in transferring the primary admin function to your client promptly. 

Here's how you can reach them:

1. Sign in to your QBOA account.
2. Click Help and tap the Search tab.
   
   
   
   
   
   
3. Select Contact Us. Provide a brief description of your concern.
4. Hit Continue.
   
   
   
   
5. Choose a way to connect:

• Callback
• Chat
  
  
  
  

Furthermore, I can share with you a workaround. You can let your client send a request to be the primary admin to our account protection team. Please refer to the steps below:

1. Gather the necessary documents to verify the rightful ownership of the account.
2. You'll need to sign in with your email to view the form. 
3. Once done, use this article to complete the form and transmit: Request to be the primary admin or contact.
4. Your case will be reviewed as soon as possible. Then, you'll receive an update via email with the status of your request.

I'm fully behind you, eager for a successful resolution that allows you to restore primary admin access to your client, dorretti. Should you have any further queries regarding user management within your account, don't hesitate to reach out to me.