Are there any common VBA settings or configurations that can indirectly contribute to VBA Error 400 when dealing with web requests?

Yes, several factors can contribute. 1) Security settings: Restrictive macro security settings might prevent VBA from making HTTP requests. 2) Proxy settings: If your network requires a proxy server, ensure VBA is configured to use it correctly. Incorrect proxy settings can cause connection errors or 400 errors. 3) Conflicting Add-ins: Certain add-ins might interfere with network requests. Try disabling add-ins to see if the issue resolves. 4) Trust Center Settings: Ensure the location where the VBA code resides is trusted. 5) Older Excel versions: Older versions might have limitations or bugs in their XMLHTTP implementation.