Anybody know why my invoices can not be viewed by customers once emailed to them? they the the 3mail but can not download to view full invoice?

Thanks for posting here in the Community, @info-automarine-. 

I understand the impact of any delay in resolving this unexpected behavior when letting your customers view their invoices. Let me guide you on how your customers would see their invoice details. 

Before we start, you can send an invoice to yourself and check if you can view the invoice. If so, you can let your customer perform basic troubleshooting steps with their browser. 

The most common display issues might be because of too many cache files in the browser. It is the possible reason your customer is unable to see your invoice details. 

To resolve this, we can let your customer open the invoice in a private browser. 

Here's how: 

• Google Chrome: CTRL + Shift + N
• Safari: Command + Shift + N 
• Mozilla Firefox and Internet Explorer: CTRL + Shift + P 

If they can view the invoice without any issues, they'll have to go back to their regular browser and then clear their browser cache to delete the stored temporary internet files. 

1. Right-click the Review and pay button in the email and copy the URL. 
2. Open a web browser and paste the link into the address bar. 
3. If the link still doesn't open, you can use other supported browsers. 
4. Make sure their web browser is up to date. 

 In addition, you'll want to make sure that your customers are using the latest version of Adobe Reader/Acrobat. QuickBooks Online uses this application to control and manipulate sales forms.

Lastly, I'm adding this article to learn how to manage the invoices you send to your customers: Create invoices in QuickBooks Self-Employed. 

Don't hesitate to post here with any concerns or questions you may have about managing invoices. The Community always has your back.