why can't i delete old invoices?

I hear you and appreciate you letting us know about the problem when deleting an invoice in QuickBooks Self-Employed (QBSE), Chris.

At this time, we have identified that the issue is linked to investigation number INV-105561. Please be assured that our engineering team is actively working to resolve this issue, and we anticipate providing you with an update shortly.

If you'd like to receive an email update on the investigation and be added to the list of affected users, you can contact our QuickBooks Self-Employed Support team. 

To reach our support team, you can follow these steps:

1. Sign in to your QuickBooks account.
2. Select the Help (?) icon.
3. Scroll down to select the Contact Us button and follow the prompts.
4. You will be able to request a callback or start a live chat with an expert.

For more details, please see this page: How to get help with QuickBooks. 

You can check out this article to learn more on how to manage invoices in QBSE: Manage invoices

Feel free to contact us if you have any further inquiries about invoices in QBSE. We'll always be here in the Community to help. Take care.