I know there are some other posts on this. So the setup I've got which is mostly working is with:
- TLS Decrpytion
- Streaming mode enabled
- Loopback Exemption for Mail and Calendar
The odd thing is that if I close Mail (and end the process since it's a background app) and start it up, then Fiddler will capture it fine. The traffic is visible, and the app will operate correctly (sync, send etc.)
However, after some time period, the capturing will stop, and then the app will stop being able to communicate as well. Even if I stop overall Fiddler capture, this will not fix the problem, nor will ending Fiddler (cancelling it's proxy), only nuking the Mail App and restarting it corrects the issue once this occurs. If I don't run Fiddler at all, it doesn't run into this problem, and always connects fine.
Seems like this probably isn't a direct Fiddler issue, I wondered if anyone had any ideas about why it might cease functioning after a time?