- Google Address Autocomplete
- Flatsome UX Builder
- ActiveCampaign
- Paypal Reference Transactions
- How PaypPal/Stripe Works
- Enabling Enfold Avia Layout Builder
- Setting Up Authorize.net for Upsell & Downsell
- Supported Payment Gateways
- Setting Up A/B Testing with Google Optimize
- Setting Quantity and Discount for Products on the Checkout Page
- Using CartFlows with Beaver Builder
- Hiding Fields on the Checkout Page
- Installing WooCommerce
- Using WooCommerce
- Using Your Theme's Header & Footer in a Step
- Embedding a Checkout Form on the CartFlows Checkout Page
- Hiding WooCommerce Pages and Products
- Using Pricing Tables
- Adding an Affiliate Program
- Setting a Flow as the Homepage
- Dynamic Offers aka Rule Engine
- Instant Layout for Checkout and Thank You Step
- Adding Products from the URL to the Checkout Page
- Setting Up A/B Testing for Steps
- Deleting Plugin Data During Uninstallation
- Importing Ready-Made Templates for Flows and Steps
- Importing and Exporting Funnels and Individual Page Builder Templates
- URL Parameters
- Replacing the Main Checkout Order with an Upsell or Downsell
- Rolling back to a Previous Version
- Flow in Test Mode
- Troubleshooting Plugin and Theme Conflicts
- Resolving the "Please Select a Simple, Virtual, and Free Product" Error
- Fixing Endless Loading on the Checkout Page
- Fixing the "We can't seem to find an order for you." Error on the Thank You Page
- Fixing the "Checkout ID Not Found" Error
- Fixing the "Session Expired" Error Message
- Resolving "Order Does Not Exist" Error on Upsell/Downsell Page
- Fixing the "Sorry, This Product Cannot Be Purchased" Error
- Resolving "No Product is Selected" Error
- Fixing Order Status Stuck at MainOrderAccepted
- Fixing the "Your Cart is Empty" Error Message
- Fixing "The Following Required Query String Data is Missing: Instance" Error
- Fixing "Page Not Found" on Checkout During Payment
- Fixing Checkout Page Redirection to Homepage
- Why Upsell/Downsell is Not Working or Being Skipped
- Enabling CartFlows Step Post Types for Page Builders
- How to Fix the "Sorry, the Content Area Was Not Found in Your Page" Error in Elementor
- Refreshing / Flushing WordPress Permalinks
- Fixing Request Timeout Errors When Importing Funnel or Step Templates
- Fixing "API Key Already Activated with Same Instance ID" Error
- Viewing CartFlows Logs
- Fixing 5XX Error When Importing Funnel / Step Templates
- Fixing Blank Page Issue When Importing CartFlows Elementor Templates
- Disabling Auto-fill of Address Fields Based on Zip Code
- Enabling Theme's Scripts & Styles Without Changing Page Template
- Disabling Auto-fill of Checkout Fields
- Allowing Cache Plugins to Cache CartFlows Pages
- Changing the "Choose a Variation" Text
- VAT Field Not Displaying for WooCommerce EU/UK VAT Compliance Plugin
- Enabling the Product Tab on Store Checkout
- Displaying the Order Summary Open on Mobile Devices
How to Fix “The Following Required Query String Data is Missing: Instance” Error
If you see the error message “The Following Required Query String Data is Missing: Instance” while activating your CartFlows Pro license, it usually means the plugin is unable to generate or retrieve a required instance ID.
This documentation explains what causes this error and how to resolve it.
When This Error Occurs
This message typically appears in the license activation popup on the Plugins page when one of the following conditions exists:
1. The Site Was Cloned or Migrated
If your website was cloned or migrated to another domain or host, the instance ID tied to your original site may no longer be valid. The plugin may not be able to generate a new instance correctly during license activation.
2. Caching Is Preventing the Instance from Being Stored
Sometimes caching (local, plugin-based, or server-level) prevents the instance ID from being stored in the database. When the API call is made to validate the license, it fails because the required instance value is missing.
How to Fix the Issue
Follow these steps to resolve the error and activate your CartFlows Pro license:
- Clear all cache on your site – including your browser, local, and server-side cache.
- Temporarily deactivate any cache plugin you have installed.
- Deactivate the CartFlows Pro plugin.
- Reactivate the CartFlows Pro plugin.
- Click the Activate License button.
- Enter your license key or API key.
- Click Activate.
Note: Always make sure to clear all cache and disable any cache plugins before activating your CartFlows Pro license to avoid conflicts with the license instance generation.
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