Why do I keep getting a message that my role has changed? There's no one else on my account, except myself, I'm a solo business.

I'll provide some details about user roles in QuickBooks Online, furcertain.

Before we start, may I ask what specific error message are you getting? QuickBooks automatically creates specific user profiles to track certain actions in the audit log. If you see a user you don't recognize, they are most likely an Online Banking Administration, Support Representative, or System Administration.

While the primary administrator is responsible for creating and managing user accounts for the company and for authorizing them to access the services. This user has access to every part of the QuickBooks account and is the person who initially set up the account. 

If you are the primary admin, you'll be the one who'll determines user roles on your account. You'll want to use the audit log so you can check if there are changes made to users and books. To do so, you can follow the steps below:

1. Go to the Gear icon and select Audit Log.
2. Select Filter.
3. Use the fields on the Filter panel to choose the appropriate User, Date, or Events filter to narrow the results.
4. Select Apply.

If no changes have been made, it could be the users you're referring to are those created by QuickBooks. To know more, read this article for more details: Use The Audit Log In QuickBooks Online.

Moreover, learn from this article about everything you need and resources for getting started with QuickBooks: Getting Started With QuickBooks Online.

Fill me in and keep in touch if you need further assistance with user roles or anything about QuickBooks. I'd be here to help.