HTTP Strict Transport Security will BLOCK your dev site if it is using a self signed certificate. And once the browser has given you that, it remembers it, so fixing it doesn’t help until you fix Firefox/Chrome.
Firefox
- Close any tabs
- Ctrl + Shift + H (Cmd + Shift + H on Mac)
- Find the site in question
- Right click, forget about this site
- Close and reopen browser
- Add certificate exception this time 😎
Chrome
- chrome://net-internals/#hsts
- type the hostname into the Query Domain
- If found, enter the domain in the Delete domain section 😎
