‘Tradebox.connector.wolfAPI.errorResponse’

When opening Tradebox you receive the following error:

“No JSON content found and type ‘Tradebox.connector.wolfAPI.errorResponse’ is not nullable. Path “”, line 0, position 0“,

This means Tradebox is making an outbound call to the Tradebox licencing API service on start up, but instead of receiving a valid response it is getting nothing at all (an empty response at line 0, position 0). The application then cannot continue and closes.

This is typically caused by a router or its firewall blocking outbound HTTPS traffic from this PC, or the PC’s own Windows Firewall treating the new network as a Public network and applying more restrictive rules.

Tradebox does not require any special port forwarding on your router. It is a desktop application that communicates outbound with marketplace APIs (such as eBay and Amazon) over standard HTTPS (port 443), so no unusual router configuration should be needed.

The most likely causes are:

Re-install Tradebox – The issue may result from Tradebox not fully installing. Try re-installing Tradebox. Instructions to uninstall Tradebox and reinstall can be found in this article; https://help.tradebox.co.uk/hc/en-gb/articles/7064539953937-Updating-V2-0-to-the-latest-version.

IP address change on the server PC — IF Tradebox is networked across multiple PCs and the server PC’s local IP address has changed (which often happens after a router replacement), any data folder path stored as an IP address may now be broken. Paths should use the PC name rather than an IP address to avoid this.

Windows Firewall rule for SQL Server — A new network profile (e.g. your PC treating the new router as a “Public” network instead of “Private”) can cause Windows Firewall to block SQL Server traffic between PCs. The firewall rule on the server PC may need to be re-checked.

SQL Server Browser service — If this service stopped during the router change or reboot, Tradebox on client PCs won’t be able to find the database. Restarting it on the server PC is worth trying.

Check your antivirus or security software — some antivirus packages (especially those with their own firewall) can block newly seen outbound connections after a network change. Temporarily disabling the antivirus firewall (not the full antivirus) to test is worth trying. If Tradebox works with it disabled, you will need to add exceptions for the Tradebox program folder.

Check the router’s firewall settings — some routers (particularly those supplied by ISPs) include a built-in firewall or content filtering that can block outbound HTTPS to certain endpoints. Check whether any such feature is enabled in the router admin panel.