Today i can not sent invoices? it says delivery error ?

Hello, ee-heating-hotma. 

I'll share some news about the error message when sending an invoice. 

We have a reported issue about the delivery error message when sending out invoices. Our engineers are currently working to resolve this as soon as possible. 

In the meantime, you'll want to save the invoices you want to send then manually email them to your customers. Here's how: 

1. Go to Sales, then click Invoices. 
2. Find the invoice you want to send, click the arrow icon beside Receive payment.
3. Select Print and save it as a PDF.
4. Email it to your customer. 

You'll also want to contact our support so they can add you to the list of affected users. That way, our engineers will be able to send you an update regarding the issue. 

I'd like to do it here, but I'm unable to access sensitive contact information. That said, there's how to contact them: 

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 reference, please see this page: How to get help with QuickBooks. 

If you need help recording your invoice payments, you can check out this article for a guide: Record invoice payments in QuickBooks Online.

I appreciate your patience while we're fixing the issue. This thread is still open if you have more questions about your invoices or other transactions in QuickBooks Online. I'm here to help.