Why am I getting an error when I try to send an estimate?

I appreciate you sharing your concern with us, ruytermobiledeta.

As I've checked our resources here, we've received reports about the Delivery Server Down error causing the inability to send out invoices or estimates. Rest assured our engineers are working on a fix to resolved this as soon as possible.

In the meantime, you can manually download your sales forms as a PDF file and send them outside QuickBooks.

Also, I'd recommend contacting our Customer Care Team to include your company in our lists of affected users and receive updates through email. 

Furthermore, you can check out this link to view updates about the issue: https://status.quickbooks.intuit.com/. 

Thanks for your patience while we're working on a fix. You're always welcome to reply below if you have other QuickBooks concerns. We'd gladly assist you further.