QuickBooks app won't let me create a new invoice. A pop up says "unable to connect to our service. Please try again later". How do I remedy this?

Thanks for reaching out to the Community.

Let's troubleshoot your QuickBooks app so you can get back to creating new invoices for your business.

If you're an Android user, here are some quick steps to clear the app's cache files:

1. Select the menu at the top right and choose Settings. 
2. Press Refresh Data and choose Yes.

On the other hand, follow these steps if you're using an iOS device:

1. Select the menu at the top right and then choose Help & Feedback. 
2. Click Refresh Data and Refresh. 

You can also browse this article to learn about the system requirements for the best experience when using QuickBooks: System requirements for QuickBooks Online.

You may want to enhance your business' communication in terms of personalizing your sales forms. Feel free to read this article: Customize invoices, estimates, and sales receipts in QuickBooks Online.

Please don't hesitate to get back to this thread if you have follow-up questions. I'll be around to help.