Let me share some details about the Recurring Transaction feature in QuickBooks Online (QBO), @penny.brass.

This feature is only available to QBO Essentials and Plus users. This is the reason why you get a page error when clicking the Recurring Transaction feature in your Simple Start subscription. If you wish to proceed in creating recurring transactions, you can upgrade your plan from the Billing & Subscription page.

Here's how you can do it:

1. Click the Gear icon on the top menu.
2. Select Account & Settings.
3. Go to the Billing & Subscription tab.
4. Then, from the QuickBooks section, select Upgrade your plan.
5. Click Choose plan for the product you want. 
6. Click Continue.
7. If prompted, enter your payment information.
8. Confirm the upgrade and your new billing, then choose Confirm Upgrade.

I've included these helpful articles for the detailed steps in upgrading your subscription, as well as the pricing and subscription levels for QBO: 

• Upgrade your QBO subscription
• Update your billing and subscription info in QBO

Additionally, you can read through these links to learn more about creating recurring transactions:

• Create recurring transactions in QBO
• How to create a recurring invoice and manage recurring transactions

I'm always around if you have further questions. Have a wonderful day!

@penny.brass 

You should upgrade your plan or have an additional app to integrate with your QBO Simple Start. Keep in mind, the discounted rate is not applicable when upgrading your plan.

https://quickbooks.grsm.io/UK