I have Fiddler v5 set up on Windows 10. I have followed the instructions for capturing iOS traffic detailed here, http://docs.telerik.com/fiddler/configure-fiddler/tasks/ConfigureForiOS
When Windows is not on a VPN, I can capture the traffic from my iPhone 8 with iOS 12.1 via Manual proxy setting and port 8888. However, when I connect to a VPN (Pulse Secure Network Connect 8.3) and then start up Fiddler, running as Administrator, I can then no longer load web pages in Safari on my iPhone and Fiddler doesn't capture any iOS traffic.
On the Tools > Options > Connections settings, I do have "Monitor all connections" checked.
What could prevent the proxy from working while on the VPN?