We can check your Settings to see if there are changes, NVO415. I've also got a few troubleshooting steps to let the Pay invoice button appear.

Let's begin by reviewing the online delivery and invoice payments from your Settings by following the steps below:

1. Go to the Gear icon and choose Accounts and Settings (Take me there).
2. From the Sales tab, click Invoice payments to tick the payment methods and hit Save.
3. Scroll down to the Online delivery section to ensure the Online invoice in the Additional email options for invoices is selected.
4. Click the Save button, then Done.

Here's an article for complete details: Receive and process payments in QuickBooks Online with QuickBooks Payments.

Additionally, go to the Payments tab (Take me there) on the Account and Settings page to see if your QuickBooks Payments account is still active and connected to your QBO account.

If everything's good, I recommend sending your invoices through a private or incognito window. This method will not save any history, so it's a good place to identify browser issues. Use these keyboard shortcuts:

• Google Chrome: press Ctrl + Shift + N
• Mozilla Firefox: press Ctrl + Shift + P
• Safari: press Command + Shift + N

If they can view the button utilizing these browsers, return to your regular browser and clear its cache. This way, you get a clean slate for a fresh start. Otherwise, use other supported browsers as an alternative.

Bookmark these resources to learn about deposit speed and troubleshoot if customers encounter errors when they select Pay Now:

• Find out when QuickBooks Payments deposits customer payments
• What to do if your customers can't pay their invoices online

I'm always here for further assistance in managing invoice payments. Add them to this thread and I'll get back to you quickly. Have a great day!