After completing the whitelist step shown here for your residential proxy plan, it is very important you test the proxies themselves. You can download the Oculus Proxies tester here to test the proxies on your device.
Before a drop specifically is when it is important to verify your proxies are working. This is to ensure there are no issues during a drop and that your setup works smoothly.
Pictured below is what a successful proxy test looks like. If your proxies return a "success" then you are good to run them.