This error is the most common QBO error. It indicates that there is already an account in QuickBooks that has the same "Display Name" as the account that is being synced.
The Display Name needs to be unique in QuickBooks, just like Account Code in Recurly.
To resolve the error, check your QBO configuration in the Recurly UI to see what you have chosen to map to Display Name in QBO.
If they have chosen First + Last Name, you will need to change the Name.
If they have chosen Company Name, you will need to provide a unique Company Name.
If you have chosen Email, you will need to provide a unique Email address.
Once you have edited the Display name in Recurly, sync again and the error should resolve.
Please note that Display Name will be used in all customer reporting within QuickBooks, as this might affect which type of Display Name you want to use for your Recurly-QBO integration.