I can help you with resolving the error you're having with your workflow, @modwattage.

The error you're having with your workflows can be caused by the piled-up cache in your regular browser. It stores temporary internet files from your browsing history. As it collects too many files, it can cause performance issues in your account.

I've got some steps to help fix this issue. First, sign in to your QBO account using a private browser. This helps isolate the issue since it doesn’t store data in the cache. Here are the following keyboard shortcuts: 

• Safari: Command + Shift + N
• Mozilla Firefox: CTRL + Shift + P
• Google Chrome: CTRL + Shift + N
• Microsoft Edge: CTRL + Shift + N

If it works, here's how to clear cache and cookies to fix issues when using QuickBooks Online. Restart your browser right after. You can also try to log in to your account using other supported browsers (Firefox, Google Chrome, Safari, Microsoft Edge) if the steps above didn’t work.

Here's also how you can create custom workflows to send reminders to your customers or internal team.

Let me know if you need further help with your workflows and or anything else. I'm always glad to help in any way I can. Have a great rest of the day!