This page is a summary of this page.

1. Navigate to

   chrome://net-internals/#hsts

2. Put the domain into the query box at the bottom of the page and click delete.

Note that Chrome will pre-load several sites with HSTS and you cannot delete these (e.g. google.com, facebook.com, twitter.com, etc).

1. Close all open tabs in Firefox.
2. Open the full History window with the keyboard shortcut Ctrl + Shift + H (Cmd + Shift + H on Mac). You must use this window or the sidebar for the below options to be available.
3. Find the site you want to delete the HSTS settings for – you can search for the site at the upper right if needed.
4. Right-click the site from the list of items and click Forget About This Site.This should clear the HSTS settings (and other cache data) for that domain.
5. Restart Firefox and visit the site. You should now be able to visit the site over HTTP/broken HTTPS. If these instructions did not work, you can try the following manual method:

1. Start by locating your Firefox profile folder through your operating system’s file explorer. You can find this folder through Firefox by navigating to about:support
2. Halfway down the page, in the Application Basics section, you will see Profile Folder. Click Open Folder.
3. Now close Firefox so that the browser does not overwrite any settings we are about to change.
4. In your Profile folder find and open the file SiteSecurityServiceState.txt. This file contains cached HSTS and HPKP (Key Pinning, a separate HTTPS mechanism) settings for domains you have visited. It may be very disorganised.
5. Search for the domain you want to clear the HSTS settings for and delete it from the file. Each entry beings with the domain name. Delete the entirety of the entry from the beginning of the desired domain name to the next listed domain. As an alternative, you can rename the existing file from a .txt to a .bak (in order to save the existing file, just in case) and allow Firefox to create an entirely new file on next start up.