I just converted to QB Online. I created new invoices, some of which send and some I just can't get to send. The addresses are correct. It doesn't even send to mine?

Thank you for raising concern here, @pwarlimont. 

I appreciate you for contacting our live support to resolve your invoice concern. I understand that sending your invoice will help you perform your daily QuickBooks Online (QBO) routines. Let me help you fix this.

Before anything else, we'd like to learn if any error message appears whenever you send an invoice to provide you with the exact fix.

In most cases, it fails to deliver once the email address is incorrect or there's a temporary issue with the recipient's email server. This is why you need to check the email address of each customer account. 

If it is correct and they haven’t received the invoice, ask them to check their junk or spam folders. You can also check your email address in QuickBooks Online which might be causing the issue.

For more info, you can read this article: Fix undelivered invoices in QuickBooks Online.

Moreover, to ensure that your email can receive the invoice copy, tick the Email me a copy at (Your email) box in the Accounts and Settings. Then, enter your email in the Copy (Cc) new invoices to address field. Here's how:

1. From the Gear icon, select Account and Settings.
2. Go to Sales. 
3. Scroll down, and click the pencil icon. on the Messages option.
4. Tick the box of Email me a copy at (Your E-mail).
5. Enter your email in the Copy (Cc) new invoices address field.
6. In the Sales form field, select Invoices and other sales forms.
7. Once done, tap Save. Then, Done.

You might want to email your sales forms in batch or later, check out this article: Email or print multiple sales forms in QuickBooks Online.

I'm still open to any follow-up questions about sending your invoices from QuickBooks Online. Take care.