Let's perform some browser troubleshooting steps to isolate the error. To start, access your QuickBooks Online (QBO) company using a private browser. Private mode prevents storing cache and cookies that might cause problems when running websites.
Here are the shortcut keys you can use:
Google Chrome: press Ctrl + Shift + N
Mozilla Firefox and Microsoft Edge: press Ctrl + Shift + P
Safari: press Command + Shift + N
When signed in, use a recurring template again.
If you no longer received the same message, go back to your regular browser and clear the cache. This will remove the stored cache or cookies to refresh your browser. If the same thing happens, use another supported browser. It could be that the one you're currently using has a temporary issue with QuickBooks.
Also, to get a list of all your recurring transactions in QuickBooks Online, you may pull up the Recurring Template List report. For the detailed steps, please see this article: Review your recurring transactions.
You can always get back here if you have other concerns or questions about using templates in QBO. I'll be here to help you. Stay safe.