- Configured HTTPS locally.
- Accessed site over HTTP (got application redirect) and HTTPS.
- Enabled HSTS.
- Accessed site over HTTPS (to set HSTS).
- Tore down HTTPS part of the server and tried to load the site over HTTP. Browser refused to load "http://" and automatically tried to load "https://". In another browser which had not received the "HSTS" header, loading over HTTP worked fine.
- Brought the HTTPS server back up, things worked fine.
- Turned off the HSTS config setting.
- Loaded a page (to set HSTS with expires 0, diabling it).
- Tore down the HTTPS part of the server again.
- Tried to load HTTP.
- Now it worked.