My customers aren't receiving the invoices that I send from QuickBooks.

Hello Smallwoodphrltd-, 

Welcome to the Community page, 

We are aware of this issue please can you follow troubleshooting in 3 solutions for you when customers aren't receiving your emails 👉https://quickbooks.intuit.com/learn-support/en-uk/help-article/manage-customers/3-solutions-customers-receiving-emails/L9ypZGV4I_GB_en_GB?uid=l4sko8el& . If not resolved please use these options as alternative ways to send forms until issue is resolved:

You can save your form as a PDF and send it via email through your business or other email address

(For invoices or estimates only) You can send your customer a link to their invoice or estimate through SMS or messenger service. Simply click on “save and share link” then select “copy link” and paste it into your SMS or messenger service.

If you have a Gmail or G-suite email account, you can use the Send with Gmail feature to send QBO forms from your own address following the steps in Use your Gmail address to send invoices (https://quickbooks.intuit.com/learn-support/en-uk/help-article/invoicing/use-gmail-address-send-invoices/L7bMJtO01_GB_en_GB?uid=l4skpaqj).

You can save your document as a PDF, print it, and send your customer their forms via mail.
 

We apologies for any inconvenience this maybe causing you and your business we are working on getting this resolve.