Why isn't my email invoice 'Pay Now' button appearing?

[sanchidecals]

Hi there,

I frequently send invoices to customers by creating a draft order and sending the invoice to their emails. I've collected payments this way for quite some time now, but recently the button to pay now in the email has not been showing up. The code for the invoice email notification is set to default and shows up in test emails, but when I try to send the invoice myself the button does not appear. 

The first image is from the test email and the second is the invoice preview and what ultimately shows up for my customers. Can someone please let me know how to fix this or if there's another way to ask for custom payments from customers?

[Brett11]

We've been having the same issue... over a dozen customers this month have had to call in payments because the payment button does not work. I've spent time with Shopify but they can't find anything wrong. They want me to get my already inconvenienced customers to screen record the failure. Kind of embarrassing to expect my customers to help troubleshoot our website failures...

[Simplyme996]

Has anyone figured out what the cause is, I’m facing the same issue.