Hi there, @JerviM. Thanks for joining this thread.

At the moment, there's an ongoing investigation (INV-102625) about QuickBooks Desktop (QBDT) Scheduled Reports failing to send. However, I appreciate your effort in trying to fix this by disabling the UAC. 

As a workaround, you can export the report as Excel and manually send it to your customers. Here's how: 

1. Select Report Center from the Reports tab.
2. Double-click the report you want to export.
3. Pick the Excel dropdown, then Create New Worksheet or Update Existing Worksheet.
4. Select Advanced if you see a message stating that the report has too many columns, then uncheck the Space between columns checkbox. Once done, click OK.
5. Tap OK when it's ready to export.

Check out this article for more info: Export reports as Excel workbooks in QuickBooks Desktop.

After that, you can convert the Excel into PDF or the style you want. Then, send it to your customer.

In the meantime, I recommend contacting QuickBooks Desktop (QBDT) to add you to the affected users list. Once updates are available, you'll be notified through email. 

If you want to personalize your report's font and style, you can read this article: Customize reports in QuickBooks Desktop.

Let me know if you have additional questions about managing your reports. We'll be willing to help. Keep safe, and have a good one.