Using Fiddler alongside HSTS

Environment

Product	Version
Fiddler Everywhere	1.0.0 and above
Google Chrome	all versions

Description

Fiddler Everywhere provides an option to use a unique Fiddler account or Google authentication. When using the Google authentication option when Google Chrome is set as the default OS browser, the callback may fail silently and Fiddler Everywhere never finishes authenticating the user.

This is due to a Google Chrome advanced setting that automatically redirects localhost HTTP traffic to HTTPS. This is known as HSTS and has a detrimental effect on the authentication flow of Fiddler Everywhere.

Solution

To resolve this, you can remove localhost from the list of addresses that Microsoft Edge enforces HSTS on. As a result, the callback is successful and Fiddler Everywhere finishes authenticating.

Take the following steps:

1. Open the Google Chrome and enter chrome://net-internals/#hsts in the address field. Chrome will open a special net-internals configuration page.
2. Locate the "Delete domain security policies" section.
3. Enter localhost into the box, then click the Delete button.
4. Start Fiddler Everywhere and use the Google authentication option again.

Here is a screenshot of the setting and what to do: