Let's make sure you'll be able to deliver your emails and get rid of your email logs, fairfield-impex.

When you said email logs, are your referring to the emails that informs that your message hasn't been sent to the recipient? Normally, these undelivered messages are caused by the server trying to send the message but is unsuccessful and didn't complete before the message expires. Thus, it indicates that there's a problem on the receiving server. As a result, you'll receive email logs that notifies you that the message you're trying to send failed. You'll just have to clear them manually by the deleting the message. 

In the meantime, to ensure you'll be able to send emails to your customer, we can perform some troubleshooting steps to fix the issue. Sometimes, your browser is full of frequently accessed page that may cause some unusual responses. You can log in to your QuickBooks Online (QBO) account in a private window. You can use the shortcuts keys below: 

• Press Ctrl + Shift + N (Google Chrome)
• Ctrl + Shift + P (Firefox)
• Control + Option + P (Safari)

Once signed in, double-check if you can already connect to our support team. If so, return to your default browser and clear the cache to speed up the loading process. The cache is sometimes overwhelmed with older data which can cause viewing and performance issues. Clearing them refreshes the system and you'll be able to to work with a clean slate. If the same thing happens, you can switch to other browser. 

In addition, you may also want to know how to record and mark your invoices as paid after you process a payment from a customer. To know more, learn from this article for more details: Record Invoice Payments In QuickBooks Online.

Let me know if you have any questions about sending email in QBO. I'll always be right here to further assist you.