I appreciate you for coming back to the thread and clarifying your issue about accepting an invitation from clients, gilesbelfrage-ic. Let me provide details on how the process works in QuickBooks. I'll also ensure you can accept the invitation without an error message so you can properly handle their books.
When accepting a client's invitation to add you as an accountant, make sure you have the same QuickBooks region as the client. If your clients are using international versions, you also need to utilize it to accept the invitation effectively. Otherwise, you will receive the same error or be required to create a new account because you are using a different country.
I recommend signing up or adding another QuickBooks Online Accountant in the same region as your client's account so you can accept the invitation. Then, make sure your clients send the invitation to the correct email address. It should be the one linked to the user ID you use to sign in and enter the correct information.
Then, once you already see your client’s account listed in the Clients tab, you’re all set to manage their books.
In case you don't want to sign up for another QBOA, you can have your client invite you as the company administrator for you to access their company file. You can provide this article to your clients on how to perform the process: Add and manage users in QuickBooks Online.
Lastly, you can read this article if you need steps on how to clean up client's books and fix incomplete transactions: Review your clients' books in QuickBooks Online Accountant.
If you require additional assistance managing your client's account, you're always welcome to leave them in the comments below. I'm looking forward to helping you further, gilesbelfrage-ic. Have a good one!
