I can help figure out why your invoices go to the client's Spam folder, patrick82.
You can send invoices to your clients as long as QuickBooks isn't blocked by your email provider or blocked from your client's settings.
You'll want to verify that from your client or you can reset your email to fix this.
If the problem continues, contact our QuickBooks Self-Employed support to pull up your account and help investigate this issue further. Here's a link on how to contact them: QBSE support.
Please let me know if you need anything else. I’ll be happy to help. Thanks for dropping by!