Let's work together and figure out why you're unable to log in to your backup data in QuickBooks Desktop, Tristian8879.
Before we move forward, could you share the exact wording of the error message you encounter when attempting to sign in? Any additional information will assist me in delivering a prompt and precise solution.
In the meantime, you can consider checking this link to fix issues when you can’t back up your QuickBooks Desktop data file with Intuit Data Protect: Unable to back up with Intuit Data Protect.
However, if you are using a third-party application that is not associated with QuickBooks, I suggest reaching out to their support team for further assistance with the backup issue.
I am eager to help you once more with any QuickBooks-related tasks or questions. Please feel free to share them in the comments below.