You can send your client an invoice in a different way in QuickBooks Online (QBO), Abdullahsadeghi56.

To better assist you, could you let us know the specific error message you encountered while attempting to send the invoice to your client? Any additional details about the issue would be greatly appreciated, as they will help us provide the most accurate resolution for your situation.

If you’re unable to send the invoice using the Review and send button, here are some alternative ways you can successfully deliver it:

Save the invoice as a PDF and send it via email:

1. On the Invoice, click the Print or download link.
    
2. Select Download to save the invoice as a PDF file.
3. Once downloaded, attach the file to your email and manually send it to your client using your preferred email address or account.

Send the invoice link via SMS or messenger service:

1. On the Invoice, click the dropdown next to the Review and send button.
    
2. Select Share link.
3. Click the Copy link button, followed by the Done button.
    
4. Paste the copied link into your text message or messaging platform and send it directly to your customer.

For additional methods to send invoices, you can refer to this article: Send an invoice to a customer.

Don’t hesitate to reach out if you need further assistance.